Merge pull request 'Tech-Debt-Cleanup: Doku, Security-Hardening, Server-Validierung, Client-Stabilitaet' (#2) from feature/techdebt-cleanup into master

Reviewed-on: #2

.github/workflows/build.yml

@@ -0,0 +1,40 @@
+name: Build
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: windows-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v4
+
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v5
+        with:
+          dotnet-version: "10.0.x"
+
+      - name: Install MAUI workload
+        run: dotnet workload install maui
+
+      - name: Restore
+        run: dotnet restore SlipItIn.slnx
+
+      - name: Build Server-Stack
+        run: |
+          dotnet build SlipItIn.Shared/SlipItIn.Shared.csproj --no-restore --configuration Release
+          dotnet build SlipItIn.ServiceDefaults/SlipItIn.ServiceDefaults.csproj --no-restore --configuration Release
+          dotnet build SlipItIn.Server/SlipItIn.Server.csproj --no-restore --configuration Release
+          dotnet build SlipItIn.Server.Tests/SlipItIn.Server.Tests.csproj --no-restore --configuration Release
+          dotnet build SlipItIn.AppHost/SlipItIn.AppHost.csproj --no-restore --configuration Release
+
+      - name: Build MAUI Client
+        run: dotnet build SlipItIn/SlipItIn.csproj --no-restore --configuration Debug
+
+      - name: Run Server Tests
+        run: dotnet test SlipItIn.Server.Tests/SlipItIn.Server.Tests.csproj --no-restore --configuration Release

.github/workflows/openwiki-update.yml

@@ -14,16 +14,21 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out repository
-        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v4
+        with:
+          # Full history so `openwiki code --update` can diff HEAD against the
+          # commit it last documented; a shallow clone hides that commit and the
+          # update runs against an empty change summary.
+          fetch-depth: 0
 
       - name: Set up Node.js
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
         with:
           node-version: "22"
 
       - name: Install OpenWiki
         # mermaid + jsdom are optional; they add high-fidelity validation of Mermaid diagrams. Remove if your wiki has none.
-        run: npm install --global openwiki@0.2.3 mermaid@11.16.0 jsdom@29.1.1
+        run: npm install --global openwiki mermaid@11.16.0 jsdom@29.1.1
 
       - name: Run OpenWiki
         run: openwiki code --update --print
@@ -32,8 +37,19 @@ jobs:
           GEMINI_API_KEY: ${{ secrets.GEMINI_API_KEY }}
           OPENWIKI_MODEL_ID: gemini-3.6-flash
 
+
+      - name: Restore protected workflow file
+        # `openwiki code --update` regenerates this file from its internal
+        # template on every run, which silently drops the guard above (see
+        # https://github.com/langchain-ai/openwiki/issues/423). Until that's
+        # fixed upstream, discard whatever the agent just wrote here so the
+        # guard always survives, regardless of whether the run above
+        # succeeded or failed.
+        if: always()
+        run: git checkout -- .github/workflows/openwiki-update.yml
+
       - name: Create OpenWiki update pull request
-        uses: peter-evans/create-pull-request@22a9089034f40e5a961c8808d113e2c98fb63676 # v7
+        uses: infinilabs/gitea-pr@v1
         with:
           add-paths: |
             openwiki
@@ -42,8 +58,12 @@ jobs:
             .github/workflows/openwiki-update.yml
           branch: openwiki/update
           commit-message: "docs: update OpenWiki"
+          url: ${{ secrets.URL }}
+          token: ${{ secrets.TOKEN }}
+          base_branch: master
+          head_branch: openwiki/update
           title: "docs: update OpenWiki"
           body: |
             Automated OpenWiki documentation update.
 
-            This PR was generated by the scheduled OpenWiki workflow.
+            This PR was generated by the scheduled OpenWiki workflow.

.gitignore

@@ -361,6 +361,8 @@ MigrationBackup/
 
 # Fody - auto-generated XML schema
 FodyWeavers.xsd
+# Legacy: urspruenglich SQLite-Dateien — die Anwendung nutzt inzwischen PostgreSQL (via Aspire).
+# Eintraege bleiben als Sicherheitsnetz, falls lokal noch alte DB-Dateien existieren.
 /SlipItIn.Server/slipitIn.db
 /SlipItIn.Server/slipitIn.db-shm
 /SlipItIn.Server/slipitIn.db-wal

AGENTS.md

@@ -2,7 +2,10 @@
 
 ## OpenWiki
 
-This repository uses OpenWiki for recurring code documentation. Start with `openwiki/quickstart.md`, then follow its links to architecture, workflows, domain concepts, operations, integrations, testing guidance, and source maps.
+This repository has a generated `openwiki/` evidence index. It is optional just-in-time context, not required startup reading.
+
+- Treat source code and tests as authoritative. A brief's unknowns and review items are verification gaps, not automatic requirements.
+- Prefer the narrowest quiet validation that proves the changed behavior. Preserve complete failure output.
 
 The scheduled OpenWiki GitHub Actions workflow refreshes the repository wiki. Do not hand-edit generated OpenWiki pages unless explicitly asked; prefer updating source code/docs and letting OpenWiki regenerate.
 

Agents/Architecture.md

@@ -1,136 +0,0 @@
-# Slip It In – Architektur-Updates (Phase 2b & 3b)
-
-Dieses Dokument fasst die Sicherheits- und Stabilitäts-Erweiterungen zusammen, die dem ProjectPlan.md hinzugefügt wurden.
-
-## 🔒 Backend-Sicherheit (Phase 2b)
-
-### 1. JWT-Claims Validation im GameHub
-- **Problem**: Clients könnten falsche PlayerId-Claims senden (Spoofing)
-- **Lösung**: `GetAuthenticatedUserId()` extrahiert User-ID aus JWT-Claims
-- **Implementierung**: Jede Hub-Methode validiert `Context.User?.FindFirst(ClaimTypes.NameIdentifier)`
-
-### 2. IDbContextFactory statt Scoped DbContext
-- **Problem**: Bei parallelen SignalR-Aufrufen kann es zu Race Conditions kommen
-- **Lösung**: `IDbContextFactory<SlipItInDbContext>` erzeugt isolierte Sessions pro Aufruf
-- **Vorteil**: Phrase-Transfer ist thread-safe, keine Conflicts bei 2 gleichzeitigen Challenges
-
-### 3. Serverseitige Validierung
-- **Regel**: Clients senden nur "Ich möchte X machen", Server prüft ALLES
-- **Beispiel**: `SubmitSlipAsync()` prüft auf dem Server:
-  - ✅ Gehört die Phrase dem Spieler?
-  - ✅ Ist die Runde aktiv?
-  - ✅ Ist der Spieler noch im Spiel?
-
-### 4. Daten-Isolation (GameStateDto vs. PlayerHandDto)
-- **GameStateDto**: Öffentliche Daten (Username, Score, CardCount) → für ALLE sichtbar
-- **PlayerHandDto**: Private Daten (Text der eigenen Karten) → nur für den Spieler selbst
-- **Ergebnis**: Gegner sehen nicht, welche Phrasen ich habe!
-
----
-
-## 📱 Client-Stabilität (Phase 3b)
-
-### 1. WeakReferenceMessenger für Event-Entkopplung
-- **Problem**: Services rufen ViewModels direkt auf → Memory Leaks wenn VM disposed
-- **Lösung**: Services senden Messages via `WeakReferenceMessenger.Default.Send()`
-- **Vorteil**: ViewModels können sich abmelden ohne zirkuläre Abhängigkeiten
-
-**Beispiel:**
-```csharp
-// Service sendet Event
-WeakReferenceMessenger.Default.Send(new GameStateChangedMessage(newState));
-
-// ViewModel empfängt (mit auto-cleanup beim Dispose)
-WeakReferenceMessenger.Default.Register<GameStateChangedMessage>(this, (r, m) =>
-{
-	CurrentGameState = m.Value;
-});
-```
-
-### 2. Automatischer Reconnect
-- **Strategie**: Exponential Backoff (0s → 2s → 10s → 30s)
-- **Pufferung**: Offline-Aktionen werden in lokale Queue geschrieben
-- **Resync**: Nach Reconnect wird `ResyncAsync()` aufgerufen
-
-**Flow:**
-1. SignalR-Verbindung getrennt
-2. Client speichert "Slip zu Phrase X" in lokale Queue
-3. Nach 2s Automatischer Reconnect-Versuch
-4. Nach erfolgreichem Reconnect: Queued Actions werden abgesendet
-
-### 3. State Restoration
-- **App-Pause**: `GameStateService` speichert aktuellen State in `SecureStorage`
-- **App-Resume**: `ResyncAsync()` wird aufgerufen
-  - ✅ Holt aktuellen GameState vom Server
-  - ✅ Sendet gepufferte Offline-Aktionen erneut
-  - ✅ UI zeigt "Syncing..." bis fertig
-
-### 4. Dual-Layer Storage
-- **In-Memory Layer**: `GameStateService` halten aktuellen State
-- **Persistent Layer**: `SecureStorage`/`Preferences` speichern Backup
-- **Fehler-Handling**: Nach App-Crash kann State aus Persistent Layer wiederhergestellt werden
-
----
-
-## 📊 Schnellreferenz: Neue Components
-
-### Backend
-```
-GameHub
-├─ GetAuthenticatedUserId()          → JWT-Validierung
-├─ ValidatePlayerAccessAsync()        → Authorization Check
-└─ Alle Methoden nutzen IDbContextFactory
-
-Program.cs
-├─ AddDbContextFactory<SlipItInDbContext>()
-├─ AddAuthentication(JwtBearerDefaults)
-└─ AddSignalR() mit JWT-Filter
-
-DTOs
-├─ GameStateDto (öffentlich)
-├─ PlayerHandDto (privat)
-└─ Keine CardText in GameStateDto!
-```
-
-### Client
-```
-GameStateService
-├─ CurrentGameState (in-memory)
-├─ CurrentPlayerHand (in-memory)
-├─ UpdateGameStateAsync() → speichert + sendet Message
-└─ ResyncAsync() → bei App-Resume
-
-SignalRService
-├─ ConnectAsync(token) mit Auto-Reconnect
-├─ RequestGameStateAsync()
-└─ On<> Handler senden Messages
-
-Messages (WeakReferenceMessenger)
-├─ GameStateChangedMessage
-├─ PlayerHandChangedMessage
-└─ ChallengeReceivedMessage
-```
-
----
-
-## 🧪 Wichtigste Tests
-
-| Test | Ziel |
-|------|------|
-| **JWT-Auth** | Hub lehnt Requests ohne gültiges Token ab |
-| **Player-Access** | User A kann nicht auf Players von User B zugreifen |
-| **Race Condition** | Phrase-Transfer ist thread-safe bei 2 gleichzeitigen Challenges |
-| **Offline-Queue** | Aktionen während Netzwerk-Ausfall werden gepuffert und später gesendet |
-| **Memory Leaks** | Keine Leaks wenn ViewModels disposed werden (WeakReference) |
-| **State-Sync** | App-Resume synct korrekt mit Server-State |
-
----
-
-## 🚀 Implementierungs-Reihenfolge
-
-1. **Backend zuerst**: JWT-Auth + IDbContextFactory konfigurieren
-2. **GameService erweitern**: Serverseitige Validierung in alle Methoden
-3. **Client-Services**: GameStateService + SignalRService implementieren
-4. **Messaging**: WeakReferenceMessenger in ViewModels integrieren
-5. **Tests**: Integrationstest-Suite schreiben
-6. **UI**: Views an neue Message-Events binden

CLAUDE.md

@@ -2,7 +2,10 @@
 
 ## OpenWiki
 
-This repository uses OpenWiki for recurring code documentation. Start with `openwiki/quickstart.md`, then follow its links to architecture, workflows, domain concepts, operations, integrations, testing guidance, and source maps.
+This repository has a generated `openwiki/` evidence index. It is optional just-in-time context, not required startup reading.
+
+- Treat source code and tests as authoritative. A brief's unknowns and review items are verification gaps, not automatic requirements.
+- Prefer the narrowest quiet validation that proves the changed behavior. Preserve complete failure output.
 
 The scheduled OpenWiki GitHub Actions workflow refreshes the repository wiki. Do not hand-edit generated OpenWiki pages unless explicitly asked; prefer updating source code/docs and letting OpenWiki regenerate.
 

README.md

@@ -1 +1,53 @@
-# SlipItIn
+# SlipItIn
+
+Ein Echtzeit-Multiplayer-Partyspiel: Jeder Spieler erhält Phrasen-Karten und versucht, sie unbemerkt in die laufende Runde zu "slippen". Wer einen fremden Slip erkennt, kann ihn anfechten — bei einer falschen Beschuldigung wandert die Phrase allerdings zum Beschuldiger.
+
+## Tech-Stack
+
+- **Client:** .NET MAUI (.NET 10) mit CommunityToolkit.Mvvm und SignalR-Client
+- **Server:** ASP.NET Core 10 Web API + SignalR, EF Core mit PostgreSQL
+- **Orchestrierung:** .NET Aspire (`SlipItIn.AppHost`) startet Server inklusive PostgreSQL-Container
+- **Shared:** Gemeinsame Modelle und DTOs in `SlipItIn.Shared`
+
+## Voraussetzungen
+
+- .NET 10 SDK
+- Docker oder Podman (für den PostgreSQL-Container, den Aspire bereitstellt)
+- MAUI-Workload: `dotnet workload install maui`
+- Für den Server allein genügt die Aspire-Workload-Unterstützung des SDKs
+
+## Ausführen
+
+```powershell
+dotnet run --project SlipItIn.AppHost/SlipItIn.AppHost.csproj
+```
+
+Der AppHost startet PostgreSQL (Container), wendet EF-Migrationen automatisch an und seedet Testdaten. Die MAUI-App verbindet sich standardmäßig mit `https://localhost:7274` (Android-Emulator: `http://10.0.2.2:5234`).
+
+## Konfiguration
+
+| Key | Zweck |
+| --- | --- |
+| `Jwt:Key` | Signaturschlüssel für JWT (mindestens 32 Zeichen). **Nicht committen** — via User-Secrets oder Umgebungsvariable setzen. In Development ist ein Fallback-Key hinterlegt; in Production bricht der Server ohne konfigurierten Key den Start ab. |
+| `Jwt:Issuer` / `Jwt:Audience` | Token-Aussteller bzw. -Empfänger (Defaults: `SlipItInServer` / `SlipItInClient`) |
+| `ConnectionStrings:postgresdb` | Wird lokal von Aspire injiziert; muss nicht manuell gesetzt werden |
+
+## Projektstruktur
+
+- `SlipItIn/` — MAUI-Client (Views, ViewModels, Services, Offline-Queue)
+- `SlipItIn.Server/` — Web API, SignalR-Hub, EF Core, Migrations
+- `SlipItIn.Shared/` — Datenbank-Entitäten und SignalR-DTOs
+- `SlipItIn.AppHost/` — Aspire-Orchestrierung
+- `SlipItIn.ServiceDefaults/` — Geteilte Aspire-Service-Defaults
+- `openwiki/` — Generierte Dokumentation (wird automatisch aktualisiert, bitte nicht von Hand editieren)
+
+## Build
+
+```powershell
+dotnet build SlipItIn.slnx
+```
+
+## Hinweise
+
+- Dokumentationssprache: Handgepflegte Dateien (diese README) sind Deutsch, die generierte OpenWiki-Dokumentation ist Englisch.
+- `.gitignore` enthält noch Einträge für `slipitIn.db` — ein Überbleibsel aus der ursprünglichen SQLite-Planung. Die Anwendung nutzt PostgreSQL.

SlipItIn.AppHost/AppHost.cs

@@ -1,8 +1,7 @@
 var builder = DistributedApplication.CreateBuilder(args);
 
 var db = builder.AddPostgres("pgsql")
-                .AddDatabase("postgresdb")
-                ;
+                .AddDatabase("postgresdb");
 
 var server = builder.AddProject<Projects.SlipItIn_Server>("server")
                     .WithReference(db)

SlipItIn.AppHost/SlipItIn.AppHost.csproj

@@ -9,8 +9,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Aspire.Hosting.AppHost" Version="13.4.6" />
-    <PackageReference Include="Aspire.Hosting.PostgreSQL" Version="13.4.6" />
+    <PackageReference Include="Aspire.Hosting.AppHost" Version="13.5.2" />
+    <PackageReference Include="Aspire.Hosting.PostgreSQL" Version="13.5.2" />
     <PackageReference Include="MessagePack" Version="3.1.8" />
   </ItemGroup>
 

SlipItIn.Server.Tests/AuthControllerTests.cs

@@ -0,0 +1,212 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Hosting;
+using SlipItIn.Server.Controllers;
+using SlipItIn.Server.Data;
+using SlipItIn.Shared.DTOs;
+using SlipItIn.Shared.Models;
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+
+namespace SlipItIn.Server.Tests;
+
+public class AuthControllerTests
+{
+    private readonly IDbContextFactory<SlipItInDbContext> _factory = TestDbHelper.CreateFactory();
+    private readonly AuthController _sut;
+
+    public AuthControllerTests()
+    {
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["Jwt:Key"] = "TestKeyThatIsAtLeast32CharactersLong!!",
+                ["Jwt:Issuer"] = "TestIssuer",
+                ["Jwt:Audience"] = "TestAudience",
+                ["Jwt:ExpirationMinutes"] = "60"
+            })
+            .Build();
+        _sut = new AuthController(_factory, config, new TestHostEnvironment());
+    }
+
+    private sealed class TestHostEnvironment : IHostEnvironment
+    {
+        public string EnvironmentName { get; set; } = Environments.Development;
+        public string ApplicationName { get; set; } = "SlipItIn.Server.Tests";
+        public string ContentRootPath { get; set; } = AppContext.BaseDirectory;
+        public Microsoft.Extensions.FileProviders.IFileProvider ContentRootFileProvider { get; set; } = null!;
+    }
+
+    // ---------- Register ----------
+
+    [Fact]
+    public async Task Register_ReturnsOk_WithTokenAndUserData()
+    {
+        var result = await _sut.Register(new RegisterRequestDto
+        {
+            Username = "  Alice  ",
+            Email = "  ALICE@Test.Local ",
+            Password = "Secret123!"
+        });
+
+        var ok = Assert.IsType<OkObjectResult>(result.Result);
+        var dto = Assert.IsType<AuthResponseDto>(ok.Value);
+        Assert.Equal("Alice", dto.Username); // getrimmt
+        Assert.Equal("alice@test.local", dto.Email); // getrimmt + lowercase
+        Assert.True(dto.UserId > 0);
+        Assert.False(string.IsNullOrWhiteSpace(dto.Token));
+        Assert.True(dto.ExpiresAtUtc > DateTime.UtcNow);
+
+        // Token enthält die erwarteten Claims und ist valide lesbar
+        var token = new JwtSecurityTokenHandler().ReadJwtToken(dto.Token);
+        Assert.Equal("TestIssuer", token.Issuer);
+        Assert.Contains("TestAudience", token.Audiences);
+        Assert.Equal(dto.UserId.ToString(), token.Claims.First(c => c.Type == ClaimTypes.NameIdentifier).Value);
+    }
+
+    [Theory]
+    [InlineData("", "a@b.c", "pw")]
+    [InlineData("user", "", "pw")]
+    [InlineData("user", "a@b.c", "")]
+    [InlineData(" ", "a@b.c", "pw")]
+    public async Task Register_ReturnsBadRequest_WhenFieldsMissing(string username, string email, string password)
+    {
+        var result = await _sut.Register(new RegisterRequestDto { Username = username, Email = email, Password = password });
+
+        Assert.IsType<BadRequestObjectResult>(result.Result);
+    }
+
+    [Fact]
+    public async Task Register_ReturnsConflict_WhenEmailExists_CaseInsensitive()
+    {
+        using var db = _factory.CreateDbContext();
+        TestDbHelper.SeedUser(db, "existing", "alice@test.local");
+
+        var result = await _sut.Register(new RegisterRequestDto
+        {
+            Username = "newuser",
+            Email = "ALICE@TEST.LOCAL",
+            Password = "Secret123!"
+        });
+
+        Assert.IsType<ConflictObjectResult>(result.Result);
+    }
+
+    [Fact]
+    public async Task Register_ReturnsConflict_WhenUsernameExists_CaseInsensitive()
+    {
+        using var db = _factory.CreateDbContext();
+        TestDbHelper.SeedUser(db, "alice", "other@test.local");
+
+        var result = await _sut.Register(new RegisterRequestDto
+        {
+            Username = "ALICE",
+            Email = "new@test.local",
+            Password = "Secret123!"
+        });
+
+        Assert.IsType<ConflictObjectResult>(result.Result);
+    }
+
+    // ---------- Login ----------
+
+    [Fact]
+    public async Task Login_ReturnsOk_WithValidCredentials()
+    {
+        using var db = _factory.CreateDbContext();
+        db.Users.Add(new User
+        {
+            Username = "bob",
+            Email = "bob@test.local",
+            PasswordHash = BCrypt.Net.BCrypt.HashPassword("Secret123!")
+        });
+        await db.SaveChangesAsync();
+
+        var result = await _sut.Login(new LoginRequestDto { Email = " BOB@test.local ", Password = "Secret123!" });
+
+        var ok = Assert.IsType<OkObjectResult>(result.Result);
+        var dto = Assert.IsType<AuthResponseDto>(ok.Value);
+        Assert.Equal("bob", dto.Username);
+        Assert.False(string.IsNullOrWhiteSpace(dto.Token));
+    }
+
+    [Theory]
+    [InlineData("", "pw")]
+    [InlineData("a@b.c", "")]
+    public async Task Login_ReturnsBadRequest_WhenFieldsMissing(string email, string password)
+    {
+        var result = await _sut.Login(new LoginRequestDto { Email = email, Password = password });
+
+        Assert.IsType<BadRequestObjectResult>(result.Result);
+    }
+
+    [Fact]
+    public async Task Login_ReturnsUnauthorized_WhenUserNotFound()
+    {
+        var result = await _sut.Login(new LoginRequestDto { Email = "ghost@test.local", Password = "Secret123!" });
+
+        Assert.IsType<UnauthorizedObjectResult>(result.Result);
+    }
+
+    [Fact]
+    public async Task Login_ReturnsUnauthorized_WhenPasswordWrong()
+    {
+        using var db = _factory.CreateDbContext();
+        db.Users.Add(new User
+        {
+            Username = "bob",
+            Email = "bob@test.local",
+            PasswordHash = BCrypt.Net.BCrypt.HashPassword("CorrectPassword")
+        });
+        await db.SaveChangesAsync();
+
+        var result = await _sut.Login(new LoginRequestDto { Email = "bob@test.local", Password = "WrongPassword" });
+
+        Assert.IsType<UnauthorizedObjectResult>(result.Result);
+    }
+
+    // ---------- Me ----------
+
+    [Fact]
+    public void Me_ReturnsUserData_FromClaims()
+    {
+        var identity = new ClaimsIdentity([
+            new Claim(ClaimTypes.NameIdentifier, "42"),
+            new Claim(ClaimTypes.Name, "alice"),
+            new Claim(ClaimTypes.Email, "alice@test.local")
+        ], "TestAuth");
+        _sut.ControllerContext = new ControllerContext
+        {
+            HttpContext = new Microsoft.AspNetCore.Http.DefaultHttpContext
+            {
+                User = new ClaimsPrincipal(identity)
+            }
+        };
+
+        var result = _sut.Me();
+
+        var ok = Assert.IsType<OkObjectResult>(result.Result);
+        var value = ok.Value!;
+        Assert.Equal(42, (int)value.GetType().GetProperty("UserId")!.GetValue(value)!);
+        Assert.Equal("alice", (string)value.GetType().GetProperty("Username")!.GetValue(value)!);
+        Assert.Equal("alice@test.local", (string)value.GetType().GetProperty("Email")!.GetValue(value)!);
+    }
+
+    [Fact]
+    public void Me_ReturnsUnauthorized_WhenNameIdentifierClaimMissing()
+    {
+        var identity = new ClaimsIdentity([new Claim(ClaimTypes.Name, "alice")], "TestAuth");
+        _sut.ControllerContext = new ControllerContext
+        {
+            HttpContext = new Microsoft.AspNetCore.Http.DefaultHttpContext
+            {
+                User = new ClaimsPrincipal(identity)
+            }
+        };
+
+        var result = _sut.Me();
+
+        Assert.IsType<UnauthorizedResult>(result.Result);
+    }
+}

SlipItIn.Server.Tests/DbSeederTests.cs

@@ -0,0 +1,61 @@
+using SlipItIn.Server.Data;
+
+namespace SlipItIn.Server.Tests;
+
+public class DbSeederTests
+{
+    [Fact]
+    public async Task SeedAsync_SeedsUsersAndPhrases_WhenDatabaseIsEmpty()
+    {
+        var factory = TestDbHelper.CreateFactory();
+        using var db = factory.CreateDbContext();
+
+        await DbSeeder.SeedAsync(db);
+
+        Assert.Equal(2, db.Users.Count());
+        Assert.True(db.Phrases.Count() >= 5);
+        Assert.All(db.Phrases, p => Assert.True(p.IsActive));
+    }
+
+    [Fact]
+    public async Task SeedAsync_DoesNothing_WhenUsersAlreadyExist()
+    {
+        var factory = TestDbHelper.CreateFactory();
+        using var db = factory.CreateDbContext();
+        TestDbHelper.SeedUser(db);
+
+        await DbSeeder.SeedAsync(db);
+
+        Assert.Equal(1, db.Users.Count());
+        Assert.Empty(db.Phrases);
+    }
+
+    [Fact]
+    public async Task SeedAsync_DoesNothing_WhenPhrasesAlreadyExist()
+    {
+        var factory = TestDbHelper.CreateFactory();
+        using var db = factory.CreateDbContext();
+        TestDbHelper.SeedPhrases(db, 1);
+
+        await DbSeeder.SeedAsync(db);
+
+        Assert.Equal(1, db.Users.Count()); // nur der Creator-User des Phrase-Seedings
+        Assert.Equal(1, db.Phrases.Count());
+    }
+
+    [Fact]
+    public async Task SeedAsync_IsIdempotent_WhenCalledTwice()
+    {
+        var factory = TestDbHelper.CreateFactory();
+        using var db = factory.CreateDbContext();
+
+        await DbSeeder.SeedAsync(db);
+        var userCount = db.Users.Count();
+        var phraseCount = db.Phrases.Count();
+
+        await DbSeeder.SeedAsync(db);
+
+        Assert.Equal(userCount, db.Users.Count());
+        Assert.Equal(phraseCount, db.Phrases.Count());
+    }
+}

SlipItIn.Server.Tests/GameHubTests.cs

@@ -0,0 +1,606 @@
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using SlipItIn.Server.Data;
+using SlipItIn.Server.Hubs;
+using SlipItIn.Server.Services;
+using SlipItIn.Shared.DTOs;
+using SlipItIn.Shared.Models;
+using System.Security.Claims;
+
+namespace SlipItIn.Server.Tests;
+
+/// <summary>
+/// Tests für den GameHub mit gemocktem IGameService und gemockten SignalR-Abhängigkeiten.
+/// Echte DB (InMemory) wird nur für die Validierungs-Methoden des Hubs verwendet.
+/// </summary>
+public class GameHubTests
+{
+    private readonly IDbContextFactory<SlipItInDbContext> _factory = TestDbHelper.CreateFactory();
+    private readonly Mock<IGameService> _gameService = new();
+    private readonly Mock<IGroupManager> _groups = new();
+    private readonly Mock<IHubCallerClients> _clients = new();
+    private readonly Mock<ISingleClientProxy> _callerProxy = new();
+    private readonly Mock<IClientProxy> _groupProxy = new();
+    private readonly Mock<ISingleClientProxy> _clientProxy = new();
+    private readonly GameHub _hub;
+
+    private const string ConnectionId = "test-connection-id";
+    private int _userId = 1;
+
+    public GameHubTests()
+    {
+        _clients.Setup(c => c.Caller).Returns(_callerProxy.Object);
+        _clients.Setup(c => c.Group(It.IsAny<string>())).Returns(_groupProxy.Object);
+        _clients.Setup(c => c.Client(It.IsAny<string>())).Returns(_clientProxy.Object);
+
+        _hub = new GameHub(_gameService.Object, _factory, NullLogger<GameHub>.Instance);
+        SetupContext();
+    }
+
+    private void SetupContext()
+    {
+        var identity = new ClaimsIdentity([new Claim(ClaimTypes.NameIdentifier, _userId.ToString())], "TestAuth");
+        var context = new Mock<HubCallerContext>();
+        context.Setup(c => c.ConnectionId).Returns(ConnectionId);
+        context.Setup(c => c.User).Returns(new ClaimsPrincipal(identity));
+        _hub.Context = context.Object;
+        _hub.Clients = _clients.Object;
+        _hub.Groups = _groups.Object;
+    }
+
+    private void WithoutAuth()
+    {
+        var context = new Mock<HubCallerContext>();
+        context.Setup(c => c.ConnectionId).Returns(ConnectionId);
+        context.Setup(c => c.User).Returns((ClaimsPrincipal?)null);
+        _hub.Context = context.Object;
+    }
+
+    private static string? ErrorMessageOf(Mock<ISingleClientProxy> proxy)
+    {
+        // Die Aufrufe kommen als SendCoreAsync(string, object?[]) mit dem Payload in args[1] rein.
+        var invocation = proxy.Invocations.FirstOrDefault(i => i.Arguments.Count >= 2 && i.Arguments[0] is string m && m == "Error");
+        if (invocation == null) return null;
+        var payload = invocation.Arguments[1];
+        // Payload kann ein anonymes Objekt sein oder ein object?[] mit einem anonymen Objekt drin.
+        if (payload is object?[] arr && arr.Length > 0) payload = arr[0];
+        return payload?.GetType().GetProperty("Message")?.GetValue(payload) as string;
+    }
+
+    private Game SeedGameWithPlayers(params (User user, string? connId)[] players)
+    {
+        using var db = _factory.CreateDbContext();
+        var game = new Game { LobbyCode = "ABC123", HostId = players[0].user.Id, Status = GameStatus.Lobby };
+        db.Games.Add(game);
+        foreach (var (user, connId) in players)
+        {
+            db.Players.Add(new Player { UserId = user.Id, Game = game, ConnectionId = connId });
+        }
+        db.SaveChanges();
+        return game;
+    }
+
+    private (User user, Player player) SeedUserWithPlayer(Game game)
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db, Guid.NewGuid().ToString("N")[..8], Guid.NewGuid().ToString("N")[..8] + "@t.local");
+        var player = new Player { UserId = user.Id, GameId = game.Id };
+        db.Players.Add(player);
+        db.SaveChanges();
+        return (user, player);
+    }
+
+    // ---------- CreateLobby ----------
+
+    [Fact]
+    public async Task CreateLobby_AddsCallerToGroupAndSendsLobbyCreated()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+
+        var game = new Game { Id = 7, LobbyCode = "XYZ789", HostId = user.Id };
+        _gameService.Setup(s => s.CreateGameAsync(user.Id, ConnectionId)).ReturnsAsync(game);
+
+        await _hub.CreateLobby();
+
+        _groups.Verify(g => g.AddToGroupAsync(ConnectionId, "XYZ789", default), Times.Once);
+        _callerProxy.Verify(p => p.SendCoreAsync("LobbyCreated", It.Is<object?[]>(a => a.Length == 1), default), Times.Once);
+    }
+
+    [Fact]
+    public async Task CreateLobby_SendsUnauthorized_WhenNotAuthenticated()
+    {
+        WithoutAuth();
+
+        await _hub.CreateLobby();
+
+        Assert.Equal("Unauthorized", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task CreateLobby_SendsGenericError_WhenServiceThrows()
+    {
+        _gameService.Setup(s => s.CreateGameAsync(It.IsAny<int>(), It.IsAny<string?>()))
+            .ThrowsAsync(new InvalidOperationException("Host not found"));
+
+        await _hub.CreateLobby();
+
+        Assert.Equal("An error occurred while creating the lobby.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- JoinLobby ----------
+
+    [Fact]
+    public async Task JoinLobby_AddsToGroupAndBroadcastsPlayerJoined()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+
+        var game = new Game { Id = 3, LobbyCode = "JOIN42", HostId = 99 };
+        _gameService.Setup(s => s.JoinGameAsync("JOIN42", user.Id, ConnectionId)).ReturnsAsync(game);
+        _gameService.Setup(s => s.GetGameStateAsync(game.Id)).ReturnsAsync(new GameStateDto { GameId = 3 });
+
+        await _hub.JoinLobby("JOIN42");
+
+        _groups.Verify(g => g.AddToGroupAsync(ConnectionId, "JOIN42", default), Times.Once);
+        _groupProxy.Verify(p => p.SendCoreAsync("PlayerJoined", It.IsAny<object?[]>(), default), Times.Once);
+    }
+
+    [Fact]
+    public async Task JoinLobby_SendsUnauthorized_WhenNotAuthenticated()
+    {
+        WithoutAuth();
+
+        await _hub.JoinLobby("ANY");
+
+        Assert.Equal("Unauthorized", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task JoinLobby_SendsServiceMessage_WhenGameFullOrStarted()
+    {
+        _gameService.Setup(s => s.JoinGameAsync(It.IsAny<string>(), It.IsAny<int>(), It.IsAny<string?>()))
+            .ThrowsAsync(new InvalidOperationException("Game is full"));
+
+        await _hub.JoinLobby("FULL1");
+
+        Assert.Equal("Game is full", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task JoinLobby_SendsGenericError_WhenUnexpectedException()
+    {
+        _gameService.Setup(s => s.JoinGameAsync(It.IsAny<string>(), It.IsAny<int>(), It.IsAny<string?>()))
+            .ThrowsAsync(new Exception("boom"));
+
+        await _hub.JoinLobby("ANY");
+
+        Assert.Equal("An error occurred while joining the lobby.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- PlayerReady ----------
+
+    [Fact]
+    public async Task PlayerReady_BroadcastsGameState_WhenValid()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((user, ConnectionId));
+        var player = db.Players.Single(p => p.GameId == game.Id);
+
+        _gameService.Setup(s => s.SetPlayerReadyAsync(game.Id, player.Id))
+            .ReturnsAsync(new Game { Id = game.Id, LobbyCode = game.LobbyCode });
+        _gameService.Setup(s => s.GetGameStateAsync(game.Id)).ReturnsAsync(new GameStateDto { GameId = game.Id });
+
+        await _hub.PlayerReady(game.Id, player.Id);
+
+        _groupProxy.Verify(p => p.SendCoreAsync("GameStateUpdated", It.IsAny<object?[]>(), default), Times.Once);
+    }
+
+    [Fact]
+    public async Task PlayerReady_SendsError_WhenPlayerBelongsToOtherUser()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db, "me", "me@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((other, null));
+        var otherPlayer = db.Players.Single(p => p.GameId == game.Id);
+
+        await _hub.PlayerReady(game.Id, otherPlayer.Id);
+
+        Assert.Equal("Player does not belong to authenticated user", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task PlayerReady_SendsGenericError_WhenServiceThrows()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((user, ConnectionId));
+        var player = db.Players.Single(p => p.GameId == game.Id);
+
+        _gameService.Setup(s => s.SetPlayerReadyAsync(It.IsAny<int>(), It.IsAny<int>()))
+            .ThrowsAsync(new InvalidOperationException("Player not found"));
+
+        await _hub.PlayerReady(game.Id, player.Id);
+
+        Assert.Equal("An error occurred while setting player status.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- StartGame ----------
+
+    [Fact]
+    public async Task StartGame_BroadcastsGameStarted_AndSendsHandsToEachPlayer()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        _userId = host.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((host, "conn-host"));
+        var (_, otherPlayer) = SeedUserWithPlayer(game);
+        using (var db2 = _factory.CreateDbContext())
+        {
+            db2.Players.Single(p => p.Id == otherPlayer.Id).ConnectionId = "conn-other";
+            db2.SaveChanges();
+        }
+
+        _gameService.Setup(s => s.StartGameAsync(game.Id)).ReturnsAsync(new Game { Id = game.Id, LobbyCode = game.LobbyCode });
+        _gameService.Setup(s => s.DealCardsAsync(game.Id)).ReturnsAsync([
+            new PlayerCard { PlayerId = game.Players.First().Id },
+            new PlayerCard { PlayerId = otherPlayer.Id }
+        ]);
+        _gameService.Setup(s => s.GetPlayerHandAsync(It.IsAny<int>())).ReturnsAsync((int pid) => new PlayerHandDto { PlayerId = pid });
+
+        await _hub.StartGame(game.Id);
+
+        _groupProxy.Verify(p => p.SendCoreAsync("GameStarted", It.IsAny<object?[]>(), default), Times.Once);
+        // Beide Spieler erhalten ihre Hand (über Clients.Client)
+        _clients.Verify(c => c.Client("conn-host"), Times.Once);
+        _clients.Verify(c => c.Client("conn-other"), Times.Once);
+        _clientProxy.Verify(p => p.SendCoreAsync("PlayerHandUpdated", It.IsAny<object?[]>(), default), Times.Exactly(2));
+    }
+
+    [Fact]
+    public async Task StartGame_SendsHostOnlyError_WhenCallerIsNotHost()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var notHost = TestDbHelper.SeedUser(db, "not", "not@t.local");
+        _userId = notHost.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((host, null), (notHost, null));
+
+        await _hub.StartGame(game.Id);
+
+        Assert.Equal("Only the host can start the game.", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task StartGame_SendsGenericError_WhenServiceThrows()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        _userId = host.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((host, null));
+
+        _gameService.Setup(s => s.StartGameAsync(It.IsAny<int>())).ThrowsAsync(new Exception("boom"));
+
+        await _hub.StartGame(game.Id);
+
+        Assert.Equal("An error occurred while starting the game.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- SubmitSlip ----------
+
+    [Fact]
+    public async Task SubmitSlip_BroadcastsSlipSubmitted_WhenValid()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((user, ConnectionId));
+        var player = db.Players.Single(p => p.GameId == game.Id);
+
+        _gameService.Setup(s => s.SubmitSlipAsync(game.Id, player.Id, 55)).ReturnsAsync(true);
+        _gameService.Setup(s => s.GetGameAsync(game.Id)).ReturnsAsync(new Game { Id = game.Id, LobbyCode = game.LobbyCode });
+
+        await _hub.SubmitSlip(game.Id, player.Id, 55);
+
+        _groupProxy.Verify(p => p.SendCoreAsync("SlipSubmitted", It.IsAny<object?[]>(), default), Times.Once);
+    }
+
+    [Fact]
+    public async Task SubmitSlip_SendsError_WhenPlayerNotOwnedByUser()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db, "me", "me@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((other, null));
+        var otherPlayer = db.Players.Single(p => p.GameId == game.Id);
+
+        await _hub.SubmitSlip(game.Id, otherPlayer.Id, 1);
+
+        Assert.Equal("Player does not belong to authenticated user", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task SubmitSlip_SendsGenericError_WhenServiceThrows()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((user, ConnectionId));
+        var player = db.Players.Single(p => p.GameId == game.Id);
+
+        _gameService.Setup(s => s.SubmitSlipAsync(It.IsAny<int>(), It.IsAny<int>(), It.IsAny<int>()))
+            .ThrowsAsync(new InvalidOperationException("Card not found"));
+
+        await _hub.SubmitSlip(game.Id, player.Id, 999);
+
+        Assert.Equal("An error occurred while submitting slip.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- ChallengeSlip ----------
+
+    [Fact]
+    public async Task ChallengeSlip_BroadcastsAndNotifiesTargetPlayer()
+    {
+        using var db = _factory.CreateDbContext();
+        var challenger = TestDbHelper.SeedUser(db, "ch", "ch@t.local");
+        _userId = challenger.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((challenger, ConnectionId));
+        var (_, targetPlayer) = SeedUserWithPlayer(game);
+        using (var db2 = _factory.CreateDbContext())
+        {
+            db2.Players.Single(p => p.Id == targetPlayer.Id).ConnectionId = "conn-target";
+            db2.SaveChanges();
+        }
+        var challengerPlayer = db.Players.Single(p => p.UserId == challenger.Id);
+
+        _gameService.Setup(s => s.CreateChallengeAsync(game.Id, challengerPlayer.Id, 42))
+            .ReturnsAsync(new SlipChallenge
+            {
+                Id = 1,
+                ChallengingPlayerId = challengerPlayer.Id,
+                TargetPlayerId = targetPlayer.Id,
+                TargetCardId = 42,
+                Status = ChallengeStatus.Pending
+            });
+        _gameService.Setup(s => s.GetGameAsync(game.Id)).ReturnsAsync(new Game { Id = game.Id, LobbyCode = game.LobbyCode });
+
+        await _hub.ChallengeSlip(game.Id, challengerPlayer.Id, 42);
+
+        _groupProxy.Verify(p => p.SendCoreAsync("SlipChallenged", It.IsAny<object?[]>(), default), Times.Once);
+        _clients.Verify(c => c.Client("conn-target"), Times.Once);
+        _clientProxy.Verify(p => p.SendCoreAsync("ChallengeReceived", It.IsAny<object?[]>(), default), Times.Once);
+    }
+
+    [Fact]
+    public async Task ChallengeSlip_SendsError_WhenPlayerNotOwnedByUser()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db, "me", "me@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((other, null));
+        var otherPlayer = db.Players.Single(p => p.GameId == game.Id);
+
+        await _hub.ChallengeSlip(game.Id, otherPlayer.Id, 1);
+
+        Assert.Equal("Player does not belong to authenticated user", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task ChallengeSlip_SendsGenericError_WhenServiceThrows()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((user, ConnectionId));
+        var player = db.Players.Single(p => p.GameId == game.Id);
+
+        _gameService.Setup(s => s.CreateChallengeAsync(It.IsAny<int>(), It.IsAny<int>(), It.IsAny<int>()))
+            .ThrowsAsync(new InvalidOperationException("No active round found"));
+
+        await _hub.ChallengeSlip(game.Id, player.Id, 1);
+
+        Assert.Equal("An error occurred while challenging slip.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- ResolveChallenge ----------
+
+    [Fact]
+    public async Task ResolveChallenge_BroadcastsAndUpdatesHands_WhenTargetResolves()
+    {
+        using var db = _factory.CreateDbContext();
+        var target = TestDbHelper.SeedUser(db, "target", "target@t.local");
+        _userId = target.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((target, "conn-target"));
+        var targetPlayer = db.Players.Single(p => p.UserId == target.Id);
+        var (_, challengingPlayer) = SeedUserWithPlayer(game);
+        using (var db2 = _factory.CreateDbContext())
+        {
+            db2.Players.Single(p => p.Id == challengingPlayer.Id).ConnectionId = "conn-challenger";
+            var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+            db2.GameRounds.Add(round);
+            var phrase = TestDbHelper.SeedPhrases(db2, 1).Single();
+            var card = new PlayerCard { PlayerId = targetPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id };
+            db2.PlayerCards.Add(card);
+            db2.SlipChallenges.Add(new SlipChallenge
+            {
+                Id = 77,
+                GameRoundId = round.Id,
+                ChallengingPlayerId = challengingPlayer.Id,
+                TargetPlayerId = targetPlayer.Id,
+                TargetCardId = card.Id,
+                Status = ChallengeStatus.Pending
+            });
+            db2.SaveChanges();
+        }
+
+        _gameService.Setup(s => s.ResolveChallengeAsync(77, true))
+            .ReturnsAsync(new SlipChallenge
+            {
+                Id = 77,
+                GameRound = new GameRound { GameId = game.Id },
+                ChallengingPlayerId = challengingPlayer.Id,
+                TargetPlayerId = targetPlayer.Id,
+                Status = ChallengeStatus.Approved
+            });
+        _gameService.Setup(s => s.GetGameAsync(game.Id)).ReturnsAsync(new Game { Id = game.Id, LobbyCode = game.LobbyCode });
+        _gameService.Setup(s => s.GetPlayerHandAsync(It.IsAny<int>())).ReturnsAsync((int pid) => new PlayerHandDto { PlayerId = pid });
+
+        await _hub.ResolveChallenge(77, true);
+
+        _groupProxy.Verify(p => p.SendCoreAsync("ChallengeResolved", It.IsAny<object?[]>(), default), Times.Once);
+        _clientProxy.Verify(p => p.SendCoreAsync("PlayerHandUpdated", It.IsAny<object?[]>(), default), Times.Exactly(2));
+    }
+
+    [Fact]
+    public async Task ResolveChallenge_SendsError_WhenCallerIsNotTarget()
+    {
+        using var db = _factory.CreateDbContext();
+        var target = TestDbHelper.SeedUser(db, "target", "target@t.local");
+        var notTarget = TestDbHelper.SeedUser(db, "not", "not@t.local");
+        _userId = notTarget.Id;
+        SetupContext();
+        var game = SeedGameWithPlayers((target, null));
+        var targetPlayer = db.Players.Single(p => p.UserId == target.Id);
+        using (var db2 = _factory.CreateDbContext())
+        {
+            db2.SlipChallenges.Add(new SlipChallenge
+            {
+                Id = 78,
+                GameRoundId = 1,
+                ChallengingPlayerId = 1,
+                TargetPlayerId = targetPlayer.Id,
+                TargetCardId = 1,
+                Status = ChallengeStatus.Pending
+            });
+            db2.SaveChanges();
+        }
+
+        await _hub.ResolveChallenge(78, true);
+
+        Assert.Equal("Only the accused player can resolve this challenge", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task ResolveChallenge_SendsMessage_WhenChallengeNotFound()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+
+        await _hub.ResolveChallenge(999, true);
+
+        Assert.Equal("Challenge not found", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- RequestGameState ----------
+
+    [Fact]
+    public async Task RequestGameState_SendsStateToCaller_WhenParticipant()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        SeedGameWithPlayers((user, ConnectionId));
+        var gameId = db.Games.Single().Id;
+
+        _gameService.Setup(s => s.GetGameStateAsync(gameId)).ReturnsAsync(new GameStateDto { GameId = gameId });
+
+        await _hub.RequestGameState(gameId);
+
+        _callerProxy.Verify(p => p.SendCoreAsync("GameStateUpdated", It.IsAny<object?[]>(), default), Times.Once);
+    }
+
+    [Fact]
+    public async Task RequestGameState_SendsError_WhenNotParticipant()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        _userId = user.Id;
+        SetupContext();
+        SeedGameWithPlayers((other, null));
+        var gameId = db.Games.Single().Id;
+
+        await _hub.RequestGameState(gameId);
+
+        Assert.Equal("User is not part of this game", ErrorMessageOf(_callerProxy));
+    }
+
+    [Fact]
+    public async Task RequestGameState_SendsGenericError_WhenServiceThrows()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        SeedGameWithPlayers((user, ConnectionId));
+        var gameId = db.Games.Single().Id;
+
+        _gameService.Setup(s => s.GetGameStateAsync(It.IsAny<int>())).ThrowsAsync(new Exception("boom"));
+
+        await _hub.RequestGameState(gameId);
+
+        Assert.Equal("An error occurred while requesting game state.", ErrorMessageOf(_callerProxy));
+    }
+
+    // ---------- OnConnectedAsync ----------
+
+    [Fact]
+    public async Task OnConnectedAsync_StoresConnectionId_WhenUserInActiveGame()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+        _userId = user.Id;
+        SetupContext();
+        SeedGameWithPlayers((user, null));
+
+        await _hub.OnConnectedAsync();
+
+        using var verify = _factory.CreateDbContext();
+        Assert.Equal(ConnectionId, verify.Players.Single(p => p.UserId == user.Id).ConnectionId);
+    }
+
+    [Fact]
+    public async Task OnConnectedAsync_DoesNotThrow_WhenNotAuthenticated()
+    {
+        WithoutAuth();
+
+        await _hub.OnConnectedAsync(); // darf nicht werfen
+    }
+
+    // ---------- OnDisconnectedAsync ----------
+
+    [Fact]
+    public async Task OnDisconnectedAsync_Completes()
+    {
+        await _hub.OnDisconnectedAsync(null);
+    }
+}

SlipItIn.Server.Tests/GameServiceTests.cs

@@ -0,0 +1,556 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging.Abstractions;
+using SlipItIn.Server.Data;
+using SlipItIn.Server.Services;
+using SlipItIn.Shared.Models;
+
+namespace SlipItIn.Server.Tests;
+
+public class GameServiceTests
+{
+    private readonly IDbContextFactory<SlipItInDbContext> _factory = TestDbHelper.CreateFactory();
+    private readonly GameService _sut;
+
+    public GameServiceTests()
+    {
+        _sut = new GameService(_factory, NullLogger<GameService>.Instance);
+    }
+
+    // ---------- CreateGameAsync ----------
+
+    [Fact]
+    public async Task CreateGameAsync_CreatesGameWithHostAsFirstPlayer()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+
+        var game = await _sut.CreateGameAsync(host.Id, "conn-1");
+
+        Assert.Equal(host.Id, game.HostId);
+        Assert.Equal(GameStatus.Lobby, game.Status);
+        Assert.Equal(6, game.LobbyCode.Length);
+        Assert.Single(game.Players);
+        Assert.Equal(host.Id, game.Players.First().UserId);
+        Assert.Equal("conn-1", game.Players.First().ConnectionId);
+    }
+
+    [Fact]
+    public async Task CreateGameAsync_Throws_WhenHostNotFound()
+    {
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.CreateGameAsync(999));
+    }
+
+    // ---------- JoinGameAsync ----------
+
+    [Fact]
+    public async Task JoinGameAsync_AddsPlayerToGame()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var joiner = TestDbHelper.SeedUser(db, "joiner", "joiner@t.local");
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+
+        var result = await _sut.JoinGameAsync(game.LobbyCode, joiner.Id, "conn-2");
+
+        Assert.Equal(game.Id, result.Id);
+        Assert.Equal(2, db.Players.Count(p => p.GameId == game.Id));
+        Assert.Equal("conn-2", db.Players.Single(p => p.UserId == joiner.Id).ConnectionId);
+    }
+
+    [Fact]
+    public async Task JoinGameAsync_Throws_WhenGameNotFound()
+    {
+        using var db = _factory.CreateDbContext();
+        var user = TestDbHelper.SeedUser(db);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.JoinGameAsync("NOCODE", user.Id));
+    }
+
+    [Fact]
+    public async Task JoinGameAsync_Throws_WhenGameAlreadyStarted()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var joiner = TestDbHelper.SeedUser(db, "joiner", "joiner@t.local");
+        var (game, _) = TestDbHelper.SeedGame(db, host, GameStatus.InProgress);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.JoinGameAsync(game.LobbyCode, joiner.Id));
+    }
+
+    [Fact]
+    public async Task JoinGameAsync_Throws_WhenGameIsFull()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        game.MaxPlayers = 1;
+        await db.SaveChangesAsync();
+        var joiner = TestDbHelper.SeedUser(db, "joiner", "joiner@t.local");
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.JoinGameAsync(game.LobbyCode, joiner.Id));
+    }
+
+    [Fact]
+    public async Task JoinGameAsync_Throws_WhenUserNotFound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.JoinGameAsync(game.LobbyCode, 999));
+    }
+
+    [Fact]
+    public async Task JoinGameAsync_Throws_WhenUserAlreadyInGame()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.JoinGameAsync(game.LobbyCode, host.Id));
+    }
+
+    // ---------- StartGameAsync ----------
+
+    [Fact]
+    public async Task StartGameAsync_SetsStatusAndCreatesFirstRound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        db.Players.Add(new Player { UserId = other.Id, GameId = game.Id });
+        await db.SaveChangesAsync();
+
+        var result = await _sut.StartGameAsync(game.Id);
+
+        Assert.Equal(GameStatus.InProgress, result.Status);
+        Assert.NotNull(result.StartedAt);
+        var round = db.GameRounds.Single(r => r.GameId == game.Id);
+        Assert.Equal(1, round.RoundNumber);
+        Assert.Equal(RoundStatus.Waiting, round.Status);
+    }
+
+    [Fact]
+    public async Task StartGameAsync_Throws_WhenGameNotFound()
+    {
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.StartGameAsync(999));
+    }
+
+    // ---------- SetPlayerReadyAsync ----------
+
+    [Fact]
+    public async Task SetPlayerReadyAsync_MarksPlayerReady()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+
+        var result = await _sut.SetPlayerReadyAsync(game.Id, hostPlayer.Id);
+
+        Assert.Equal(game.Id, result.Id);
+        using var verify = _factory.CreateDbContext();
+        Assert.True(verify.Players.Single(p => p.Id == hostPlayer.Id).IsReady);
+    }
+
+    [Fact]
+    public async Task SetPlayerReadyAsync_Throws_WhenPlayerNotFound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.SetPlayerReadyAsync(game.Id, 999));
+    }
+
+    // ---------- DealCardsAsync ----------
+
+    [Fact]
+    public async Task DealCardsAsync_DealsFiveCardsPerPlayerAndActivatesRound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        db.Players.Add(new Player { UserId = other.Id, GameId = game.Id });
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Waiting };
+        db.GameRounds.Add(round);
+        TestDbHelper.SeedPhrases(db, 10);
+        await db.SaveChangesAsync();
+
+        var cards = await _sut.DealCardsAsync(game.Id);
+
+        Assert.Equal(10, cards.Count); // 2 Spieler x 5 Karten
+        Assert.Equal(5, cards.Count(c => c.PlayerId == game.Players.First().Id));
+        Assert.All(cards, c => Assert.False(c.IsUsed));
+        using var verify = _factory.CreateDbContext();
+        Assert.Equal(RoundStatus.Active, verify.GameRounds.Single(r => r.Id == round.Id).Status);
+    }
+
+    [Fact]
+    public async Task DealCardsAsync_Throws_WhenNoWaitingRound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        TestDbHelper.SeedPhrases(db, 10);
+        await db.SaveChangesAsync();
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.DealCardsAsync(game.Id));
+    }
+
+    [Fact]
+    public async Task DealCardsAsync_Throws_WhenNotEnoughPhrases()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        db.GameRounds.Add(new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Waiting });
+        TestDbHelper.SeedPhrases(db, 4);
+        await db.SaveChangesAsync();
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.DealCardsAsync(game.Id));
+    }
+
+    // ---------- SubmitSlipAsync ----------
+
+    [Fact]
+    public async Task SubmitSlipAsync_MarksCardAsUsed()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host, GameStatus.InProgress);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var card = new PlayerCard { PlayerId = hostPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id };
+        db.PlayerCards.Add(card);
+        await db.SaveChangesAsync();
+
+        var result = await _sut.SubmitSlipAsync(game.Id, hostPlayer.Id, card.Id);
+
+        Assert.True(result);
+        using var verify = _factory.CreateDbContext();
+        Assert.True(verify.PlayerCards.Single(c => c.Id == card.Id).IsUsed);
+    }
+
+    [Fact]
+    public async Task SubmitSlipAsync_Throws_WhenCardNotFound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host, GameStatus.InProgress);
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.SubmitSlipAsync(game.Id, 1, 999));
+    }
+
+    [Fact]
+    public async Task SubmitSlipAsync_Throws_WhenCardBelongsToOtherPlayer()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host, GameStatus.InProgress);
+        var otherPlayer = new Player { UserId = other.Id, GameId = game.Id };
+        db.Players.Add(otherPlayer);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var card = new PlayerCard { PlayerId = hostPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id };
+        db.PlayerCards.Add(card);
+        await db.SaveChangesAsync();
+
+        // otherPlayer versucht, die Karte des Hosts zu verwenden
+        await Assert.ThrowsAsync<UnauthorizedAccessException>(() => _sut.SubmitSlipAsync(game.Id, otherPlayer.Id, card.Id));
+    }
+
+    // ---------- CreateChallengeAsync ----------
+
+    [Fact]
+    public async Task CreateChallengeAsync_CreatesPendingChallenge()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+        var otherPlayer = new Player { UserId = other.Id, GameId = game.Id };
+        db.Players.Add(otherPlayer);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var card = new PlayerCard { PlayerId = otherPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id, IsUsed = true };
+        db.PlayerCards.Add(card);
+        await db.SaveChangesAsync();
+
+        var challenge = await _sut.CreateChallengeAsync(game.Id, hostPlayer.Id, card.Id);
+
+        Assert.Equal(round.Id, challenge.GameRoundId);
+        Assert.Equal(hostPlayer.Id, challenge.ChallengingPlayerId);
+        Assert.Equal(otherPlayer.Id, challenge.TargetPlayerId);
+        Assert.Equal(card.Id, challenge.TargetCardId);
+        Assert.Equal(ChallengeStatus.Pending, challenge.Status);
+    }
+
+    [Fact]
+    public async Task CreateChallengeAsync_Throws_WhenTargetCardNotFound()
+    {
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.CreateChallengeAsync(1, 1, 999));
+    }
+
+    [Fact]
+    public async Task CreateChallengeAsync_Throws_WhenNoActiveRound()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Waiting };
+        db.GameRounds.Add(round);
+        var card = new PlayerCard { PlayerId = hostPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id };
+        db.PlayerCards.Add(card);
+        await db.SaveChangesAsync();
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.CreateChallengeAsync(game.Id, hostPlayer.Id, card.Id));
+    }
+
+    [Fact]
+    public async Task CreateChallengeAsync_Throws_WhenChallengerNotInGame()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var outsider = TestDbHelper.SeedUser(db, "outsider", "outsider@t.local");
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+        var otherPlayer = new Player { UserId = other.Id, GameId = game.Id };
+        db.Players.Add(otherPlayer);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var card = new PlayerCard { PlayerId = otherPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id, IsUsed = true };
+        db.PlayerCards.Add(card);
+        await db.SaveChangesAsync();
+
+        // outsider ist nicht in diesem Spiel und versucht eine Challenge anzulegen
+        await Assert.ThrowsAsync<UnauthorizedAccessException>(
+            () => _sut.CreateChallengeAsync(game.Id, hostPlayer.Id + 1000, card.Id));
+    }
+
+    [Fact]
+    public async Task CreateChallengeAsync_Throws_WhenChallengerFromOtherGame()
+    {
+        using var db = _factory.CreateDbContext();
+        var hostA = TestDbHelper.SeedUser(db, "hostA", "hostA@t.local");
+        var hostB = TestDbHelper.SeedUser(db, "hostB", "hostB@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (gameA, hostPlayerA) = TestDbHelper.SeedGame(db, hostA);
+        var (gameB, _) = TestDbHelper.SeedGame(db, hostB);
+        var otherPlayerB = new Player { UserId = other.Id, GameId = gameB.Id };
+        db.Players.Add(otherPlayerB);
+        var roundB = new GameRound { GameId = gameB.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(roundB);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var cardB = new PlayerCard { PlayerId = otherPlayerB.Id, PhraseId = phrase.Id, GameRoundId = roundB.Id, IsUsed = true };
+        db.PlayerCards.Add(cardB);
+        await db.SaveChangesAsync();
+
+        // hostPlayerA gehört zu gameA, versucht aber eine Karte aus gameB zu challengen
+        await Assert.ThrowsAsync<UnauthorizedAccessException>(
+            () => _sut.CreateChallengeAsync(gameB.Id, hostPlayerA.Id, cardB.Id));
+    }
+
+    // ---------- ResolveChallengeAsync ----------
+
+    [Fact]
+    public async Task ResolveChallengeAsync_Approved_TransfersCardToChallenger()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+        var otherPlayer = new Player { UserId = other.Id, GameId = game.Id };
+        db.Players.Add(otherPlayer);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var card = new PlayerCard { PlayerId = otherPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id, IsUsed = true };
+        db.PlayerCards.Add(card);
+        var challenge = new SlipChallenge
+        {
+            GameRoundId = round.Id,
+            ChallengingPlayerId = hostPlayer.Id,
+            TargetPlayerId = otherPlayer.Id,
+            TargetCardId = card.Id,
+            Status = ChallengeStatus.Pending
+        };
+        db.SlipChallenges.Add(challenge);
+        await db.SaveChangesAsync();
+
+        var result = await _sut.ResolveChallengeAsync(challenge.Id, approved: true);
+
+        Assert.Equal(ChallengeStatus.Approved, result.Status);
+        Assert.NotNull(result.ResolvedAt);
+        // Berechtigte Beschuldigung: Karte geht an den Beschuldiger
+        using var verify = _factory.CreateDbContext();
+        Assert.Equal(hostPlayer.Id, verify.PlayerCards.Single(c => c.Id == card.Id).PlayerId);
+    }
+
+    [Fact]
+    public async Task ResolveChallengeAsync_Rejected_KeepsCardWithTargetPlayer()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db, "host", "host@t.local");
+        var other = TestDbHelper.SeedUser(db, "other", "other@t.local");
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+        var otherPlayer = new Player { UserId = other.Id, GameId = game.Id };
+        db.Players.Add(otherPlayer);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrase = TestDbHelper.SeedPhrases(db, 1).Single();
+        var card = new PlayerCard { PlayerId = otherPlayer.Id, PhraseId = phrase.Id, GameRoundId = round.Id, IsUsed = true };
+        db.PlayerCards.Add(card);
+        var challenge = new SlipChallenge
+        {
+            GameRoundId = round.Id,
+            ChallengingPlayerId = hostPlayer.Id,
+            TargetPlayerId = otherPlayer.Id,
+            TargetCardId = card.Id,
+            Status = ChallengeStatus.Pending
+        };
+        db.SlipChallenges.Add(challenge);
+        await db.SaveChangesAsync();
+
+        var result = await _sut.ResolveChallengeAsync(challenge.Id, approved: false);
+
+        Assert.Equal(ChallengeStatus.Rejected, result.Status);
+        Assert.NotNull(result.ResolvedAt);
+        // Falsche Beschuldigung: Karte bleibt beim Beschuldigten
+        using var verify = _factory.CreateDbContext();
+        Assert.Equal(otherPlayer.Id, verify.PlayerCards.Single(c => c.Id == card.Id).PlayerId);
+    }
+
+    [Fact]
+    public async Task ResolveChallengeAsync_Throws_WhenChallengeNotFound()
+    {
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.ResolveChallengeAsync(999, true));
+    }
+
+    // ---------- GetGameStateAsync ----------
+
+    [Fact]
+    public async Task GetGameStateAsync_ReturnsStateWithoutRound_WhenNoRoundsExist()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+
+        var state = await _sut.GetGameStateAsync(game.Id);
+
+        Assert.Equal(game.Id, state.GameId);
+        Assert.Equal(game.LobbyCode, state.LobbyCode);
+        Assert.Equal("Lobby", state.Status);
+        Assert.Single(state.Players);
+        Assert.Equal(host.Username, state.Players[0].Username);
+        Assert.Equal(0, state.CurrentRound);
+        Assert.Equal(45, state.RoundTimeRemaining); // Default RoundDurationSeconds
+    }
+
+    [Fact]
+    public async Task GetGameStateAsync_ComputesRemainingTime_WhenRoundActive()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        game.RoundDurationSeconds = 45;
+        db.GameRounds.Add(new GameRound
+        {
+            GameId = game.Id,
+            RoundNumber = 2,
+            Status = RoundStatus.Active,
+            StartedAt = DateTime.UtcNow.AddSeconds(-20)
+        });
+        await db.SaveChangesAsync();
+
+        var state = await _sut.GetGameStateAsync(game.Id);
+
+        Assert.Equal(2, state.CurrentRound);
+        Assert.InRange(state.RoundTimeRemaining, 24, 25);
+    }
+
+    [Fact]
+    public async Task GetGameStateAsync_ClampsRemainingTimeToZero_WhenRoundExpired()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+        db.GameRounds.Add(new GameRound
+        {
+            GameId = game.Id,
+            RoundNumber = 1,
+            Status = RoundStatus.Active,
+            StartedAt = DateTime.UtcNow.AddSeconds(-120)
+        });
+        await db.SaveChangesAsync();
+
+        var state = await _sut.GetGameStateAsync(game.Id);
+
+        Assert.Equal(0, state.RoundTimeRemaining);
+    }
+
+    [Fact]
+    public async Task GetGameStateAsync_Throws_WhenGameNotFound()
+    {
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.GetGameStateAsync(999));
+    }
+
+    // ---------- GetPlayerHandAsync ----------
+
+    [Fact]
+    public async Task GetPlayerHandAsync_ReturnsCardsWithPhraseText()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, hostPlayer) = TestDbHelper.SeedGame(db, host);
+        var round = new GameRound { GameId = game.Id, RoundNumber = 1, Status = RoundStatus.Active };
+        db.GameRounds.Add(round);
+        var phrases = TestDbHelper.SeedPhrases(db, 2);
+        db.PlayerCards.Add(new PlayerCard { PlayerId = hostPlayer.Id, PhraseId = phrases[0].Id, GameRoundId = round.Id });
+        db.PlayerCards.Add(new PlayerCard { PlayerId = hostPlayer.Id, PhraseId = phrases[1].Id, GameRoundId = round.Id, IsUsed = true });
+        await db.SaveChangesAsync();
+
+        var hand = await _sut.GetPlayerHandAsync(hostPlayer.Id);
+
+        Assert.Equal(hostPlayer.Id, hand.PlayerId);
+        Assert.Equal(2, hand.Cards.Count);
+        Assert.Contains(hand.Cards, c => c.Text == "Phrase 1" && !c.IsUsed);
+        Assert.Contains(hand.Cards, c => c.Text == "Phrase 2" && c.IsUsed);
+    }
+
+    [Fact]
+    public async Task GetPlayerHandAsync_ReturnsEmptyHand_WhenNoCards()
+    {
+        var hand = await _sut.GetPlayerHandAsync(999);
+
+        Assert.Equal(999, hand.PlayerId);
+        Assert.Empty(hand.Cards);
+    }
+
+    // ---------- GetGameAsync ----------
+
+    [Fact]
+    public async Task GetGameAsync_ReturnsGame()
+    {
+        using var db = _factory.CreateDbContext();
+        var host = TestDbHelper.SeedUser(db);
+        var (game, _) = TestDbHelper.SeedGame(db, host);
+
+        var result = await _sut.GetGameAsync(game.Id);
+
+        Assert.Equal(game.Id, result.Id);
+    }
+
+    [Fact]
+    public async Task GetGameAsync_Throws_WhenGameNotFound()
+    {
+        await Assert.ThrowsAsync<InvalidOperationException>(() => _sut.GetGameAsync(999));
+    }
+}

SlipItIn.Server.Tests/SlipItIn.Server.Tests.csproj

@@ -0,0 +1,33 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="10.0.1">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.10" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.9.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="4.0.0">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\SlipItIn.Server\SlipItIn.Server.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

SlipItIn.Server.Tests/TestDbHelper.cs

@@ -0,0 +1,56 @@
+using Microsoft.EntityFrameworkCore;
+using SlipItIn.Server.Data;
+using SlipItIn.Shared.Models;
+
+namespace SlipItIn.Server.Tests;
+
+/// <summary>
+/// Hilfsmethoden zum Erstellen isolierter InMemory-DbContexts und Testdaten.
+/// </summary>
+public static class TestDbHelper
+{
+    public static IDbContextFactory<SlipItInDbContext> CreateFactory()
+    {
+        var options = new DbContextOptionsBuilder<SlipItInDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .Options;
+        return new TestDbContextFactory(options);
+    }
+
+    public static User SeedUser(SlipItInDbContext db, string username = "user", string email = "user@test.local", bool isActive = true)
+    {
+        var user = new User { Username = username, Email = email, PasswordHash = "hash", IsActive = isActive };
+        db.Users.Add(user);
+        db.SaveChanges();
+        return user;
+    }
+
+    public static List<Phrase> SeedPhrases(SlipItInDbContext db, int count, bool isActive = true)
+    {
+        var creator = SeedUser(db, "creator-" + Guid.NewGuid().ToString("N")[..8], Guid.NewGuid().ToString("N")[..8] + "@t.local");
+        var phrases = Enumerable.Range(1, count)
+            .Select(i => new Phrase { Text = $"Phrase {i}", CreatorId = creator.Id, IsActive = isActive })
+            .ToList();
+        db.Phrases.AddRange(phrases);
+        db.SaveChanges();
+        return phrases;
+    }
+
+    /// <summary>Erstellt ein Spiel inkl. Host-Spieler über den echten GameService-Pfad (direkt in DB).</summary>
+    public static (Game game, Player hostPlayer) SeedGame(SlipItInDbContext db, User host, GameStatus status = GameStatus.Lobby)
+    {
+        var game = new Game { LobbyCode = Guid.NewGuid().ToString("N")[..6].ToUpper(), HostId = host.Id, Status = status };
+        var hostPlayer = new Player { UserId = host.Id, Game = game };
+        game.Players.Add(hostPlayer);
+        db.Games.Add(game);
+        db.SaveChanges();
+        return (game, hostPlayer);
+    }
+
+    private class TestDbContextFactory(DbContextOptions<SlipItInDbContext> options) : IDbContextFactory<SlipItInDbContext>
+    {
+        public SlipItInDbContext CreateDbContext() => new(options);
+        public Task<SlipItInDbContext> CreateDbContextAsync(CancellationToken cancellationToken = default)
+            => Task.FromResult(new SlipItInDbContext(options));
+    }
+}

SlipItIn.Server/Controllers/AuthController.cs

@@ -17,11 +17,13 @@ public class AuthController : ControllerBase
 {
     private readonly IDbContextFactory<SlipItInDbContext> _contextFactory;
     private readonly IConfiguration _configuration;
+    private readonly IHostEnvironment _environment;
 
-    public AuthController(IDbContextFactory<SlipItInDbContext> contextFactory, IConfiguration configuration)
+    public AuthController(IDbContextFactory<SlipItInDbContext> contextFactory, IConfiguration configuration, IHostEnvironment environment)
     {
         _contextFactory = contextFactory;
         _configuration = configuration;
+        _environment = environment;
     }
 
     [HttpPost("register")]
@@ -30,6 +32,9 @@ public class AuthController : ControllerBase
         if (string.IsNullOrWhiteSpace(request.Username) || string.IsNullOrWhiteSpace(request.Email) || string.IsNullOrWhiteSpace(request.Password))
             return BadRequest("Username, Email und Passwort sind erforderlich.");
 
+        if (request.Password.Length < 8)
+            return BadRequest("Das Passwort muss mindestens 8 Zeichen lang sein.");
+
         using var context = _contextFactory.CreateDbContext();
 
         var normalizedEmail = request.Email.Trim().ToLowerInvariant();
@@ -86,7 +91,7 @@ public class AuthController : ControllerBase
 
         return Ok(new
         {
-            UserId = int.Parse(userIdClaim),
+            UserId = int.TryParse(userIdClaim, out var parsedUserId) ? parsedUserId : 0,
             Username = username,
             Email = email
         });
@@ -94,7 +99,13 @@ public class AuthController : ControllerBase
 
     private AuthResponseDto CreateAuthResponse(User user)
     {
-        var jwtKey = _configuration["Jwt:Key"] ?? "YourSuperSecretKeyThatIsAtLeast32CharactersLong!";
+        var jwtKey = _configuration["Jwt:Key"];
+        if (string.IsNullOrWhiteSpace(jwtKey))
+        {
+            if (!_environment.IsDevelopment())
+                throw new InvalidOperationException("Jwt:Key ist nicht konfiguriert.");
+            jwtKey = "DevOnlyKey-NotForProduction-ChangeMe-0123456789abcdef";
+        }
         var jwtIssuer = _configuration["Jwt:Issuer"] ?? "SlipItInServer";
         var jwtAudience = _configuration["Jwt:Audience"] ?? "SlipItInClient";
         var expirationMinutes = int.TryParse(_configuration["Jwt:ExpirationMinutes"], out var parsedMinutes) ? parsedMinutes : 1440;

SlipItIn.Server/Data/DbSeeder.cs

@@ -0,0 +1,89 @@
+using Microsoft.EntityFrameworkCore;
+using SlipItIn.Shared.Models;
+
+namespace SlipItIn.Server.Data;
+
+/// <summary>
+/// Befüllt die Datenbank mit Testdaten (2 Testuser, einige Dutzend Phrasen),
+/// wenn sie leer ist. Dient der Erleichterung manueller Tests.
+/// </summary>
+public static class DbSeeder
+{
+    public static async Task SeedAsync(SlipItInDbContext context)
+    {
+        // Nur seeden, wenn die Datenbank leer ist
+        if (await context.Users.AnyAsync() || await context.Phrases.AnyAsync())
+            return;
+
+        var alice = new User
+        {
+            Username = "alice",
+            Email = "alice@test.local",
+            PasswordHash = BCrypt.Net.BCrypt.HashPassword("Test123!")
+        };
+
+        var bob = new User
+        {
+            Username = "bob",
+            Email = "bob@test.local",
+            PasswordHash = BCrypt.Net.BCrypt.HashPassword("Test123!")
+        };
+
+        context.Users.AddRange(alice, bob);
+        await context.SaveChangesAsync();
+
+        var phrases = new[]
+        {
+            "Das hat mir meine Oma schon immer gesagt.",
+            "Ich hab da mal eine Doku gesehen.",
+            "Das ist wie damals in der Grundschule.",
+            "Das muss man sich mal auf der Zunge zergehen lassen.",
+            "Da kommt mir direkt ein Lied in den Sinn.",
+            "Das ist wie beim Autofahren: Bremsen kann man immer noch.",
+            "Ich habe das Gefühl, wir reden aneinander vorbei.",
+            "Das würde ich an deiner Stelle nochmal überdenken.",
+            "Ich glaube, da steckt mehr dahinter.",
+            "Also ich finde, das riecht verdächtig nach Montag.",
+            "Das schmeckt nach mehr.",
+            "Da ist der Wurm drin.",
+            "Das hat hand und Fuß.",
+            "Das ist ein zweischneidiges Schwert.",
+            "Da liegt der Hase im Pfeffer.",
+            "Das ist wie ein guter Wein – wird mit den Jahren besser.",
+            "Ich würde sagen: Glück im Unglück.",
+            "Das ist schon fast eine Wissenschaft für sich.",
+            "Man muss das Kind beim Namen nennen.",
+            "Das ist wie Weihnachten und Geburtstag zusammen.",
+            "Da geht mir das Herz auf.",
+            "Ich würde das jetzt nicht überbewerten.",
+            "Das kommt mir spanisch vor.",
+            "Das ist das Beste seit geschnittenem Brot.",
+            "Da bleibt kein Auge trocken.",
+            "Das ist wie Nägel mit Köpfen machen.",
+            "Ich habe da so eine Vermutung.",
+            "Das ist wie ein roter Faden.",
+            "Da platzt mir gleich der Kragen.",
+            "Ich bin da ganz bei dir.",
+            "Das muss man erstmal sacken lassen.",
+            "Das ist wie ein offenes Buch.",
+            "Da würde ich nicht drauf wetten.",
+            "Das ist wie eine Achterbahn der Gefühle.",
+            "Ich hab da ein ganz mieses Gefühl bei.",
+            "Das ist wie ein Dorn im Auge."
+        };
+
+        var random = new Random(42);
+        var creators = new[] { alice, bob };
+
+        foreach (var text in phrases)
+        {
+            context.Phrases.Add(new Phrase
+            {
+                Text = text,
+                CreatorId = creators[random.Next(creators.Length)].Id
+            });
+        }
+
+        await context.SaveChangesAsync();
+    }
+}

SlipItIn.Server/Hubs/GameHub.cs

@@ -142,6 +142,7 @@ public class GameHub : Hub
         }
         catch (InvalidOperationException ex)
         {
+            // Geprüfte Fachfehler mit festen, harmonsierten Texten dürfen an den Client.
             await Clients.Caller.SendAsync("Error", new { Message = ex.Message });
         }
         catch (Exception ex)
@@ -259,10 +260,16 @@ public class GameHub : Hub
             var challenge = await _gameService.CreateChallengeAsync(gameId, challengingPlayerId, targetCardId);
             var game = await _gameService.GetGameAsync(gameId);
 
+            using var context = _contextFactory.CreateDbContext();
+            var challengingPlayer = await context.Players
+                .Include(p => p.User)
+                .FirstOrDefaultAsync(p => p.Id == challengingPlayerId);
+
             var challengeDto = new SlipChallengeDto
             {
                 ChallengeId = challenge.Id,
                 ChallengingPlayerId = challengingPlayerId,
+                ChallengingPlayerName = challengingPlayer?.User.Username ?? string.Empty,
                 TargetPlayerId = challenge.TargetPlayerId,
                 TargetCardId = targetCardId,
                 Status = challenge.Status.ToString(),
@@ -272,7 +279,6 @@ public class GameHub : Hub
             await Clients.Group(game.LobbyCode).SendAsync("SlipChallenged", challengeDto);
 
             // Sende direkte Notification an den beschuldigten Spieler
-            using var context = _contextFactory.CreateDbContext();
             var targetPlayer = await context.Players.FindAsync(challenge.TargetPlayerId);
             if (targetPlayer?.ConnectionId != null)
             {
@@ -372,9 +378,26 @@ public class GameHub : Hub
             {
                 player.ConnectionId = Context.ConnectionId;
                 await context.SaveChangesAsync();
+
+                // (Re-)Join der Lobby-Gruppe, damit Group-Broadcasts nach einem Reconnect wieder ankommen.
+                var lobbyCode = await context.Games
+                    .Where(g => g.Id == player.GameId)
+                    .Select(g => g.LobbyCode)
+                    .FirstAsync();
+                await Groups.AddToGroupAsync(Context.ConnectionId, lobbyCode);
+
+                // Der Client bekommt nach einem Reconnect keinen vollständigen Zustand
+                // mehr aus der Queue gespielt — er muss RequestGameState aufrufen.
             }
         }
-        catch { /* Ignorieren falls nicht authentifiziert */ }
+        catch (UnauthorizedAccessException)
+        {
+            // Nicht authentifiziert — ConnectionId wird nicht gespeichert.
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(ex, "Failed to register connection for authenticated user");
+        }
 
         await base.OnConnectedAsync();
     }
@@ -382,6 +405,23 @@ public class GameHub : Hub
     public override async Task OnDisconnectedAsync(Exception? exception)
     {
         _logger.LogInformation("Client {ConnectionId} disconnected", Context.ConnectionId);
+
+        // ConnectionId zurücksetzen, damit keine Nachrichten an eine tote Verbindung gehen.
+        try
+        {
+            using var context = _contextFactory.CreateDbContext();
+            var players = await context.Players
+                .Where(p => p.ConnectionId == Context.ConnectionId)
+                .ToListAsync();
+            foreach (var player in players)
+                player.ConnectionId = null;
+            await context.SaveChangesAsync();
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(ex, "Failed to clear connection id on disconnect");
+        }
+
         await base.OnDisconnectedAsync(exception);
-    }   
+    }
 }

SlipItIn.Server/Program.cs

@@ -4,6 +4,7 @@ using Microsoft.IdentityModel.Tokens;
 using SlipItIn.Server.Data;
 using SlipItIn.Server.Hubs;
 using SlipItIn.Server.Services;
+using System.Security.Claims;
 using System.Text;
 
 var builder = WebApplication.CreateBuilder(args);
@@ -13,13 +14,27 @@ builder.AddServiceDefaults();
 
 builder.AddNpgsqlDataSource(connectionName: "postgresdb");
 
-builder.Services.AddDbContextFactory<SlipItInDbContext>(options => options.UseNpgsql());
+builder.Services.AddDbContextFactory<SlipItInDbContext>((sp, options) =>
+    options.UseNpgsql(sp.GetRequiredService<Npgsql.NpgsqlDataSource>()));
 
 // Services registrieren
 builder.Services.AddTransient<IGameService, GameService>();
 
 // JWT Authentication
-var jwtKey = builder.Configuration["Jwt:Key"] ?? "YourSuperSecretKeyThatIsAtLeast32CharactersLong!";
+var jwtKey = builder.Configuration["Jwt:Key"];
+if (string.IsNullOrWhiteSpace(jwtKey) || jwtKey.Length < 32)
+{
+    if (builder.Environment.IsDevelopment())
+    {
+        jwtKey = "DevOnlyKey-NotForProduction-ChangeMe-0123456789abcdef";
+    }
+    else
+    {
+        throw new InvalidOperationException(
+            "Jwt:Key ist nicht konfiguriert oder kürzer als 32 Zeichen. " +
+            "In Production muss ein eigener Schlüssel via Konfiguration/Umgebungsvariable gesetzt werden.");
+    }
+}
 var jwtIssuer = builder.Configuration["Jwt:Issuer"] ?? "SlipItInServer";
 var jwtAudience = builder.Configuration["Jwt:Audience"] ?? "SlipItInClient";
 
@@ -50,6 +65,24 @@ builder.Services
                     context.Token = accessToken;
                 }
                 return Task.CompletedTask;
+            },
+            OnTokenValidated = async context =>
+            {
+                var userIdClaim = context.Principal?.FindFirst(ClaimTypes.NameIdentifier)?.Value;
+                if (!int.TryParse(userIdClaim, out var userId))
+                {
+                    context.Fail("Invalid user claim.");
+                    return;
+                }
+
+                var dbFactory = context.HttpContext.RequestServices.GetRequiredService<IDbContextFactory<SlipItInDbContext>>();
+                await using var db = await dbFactory.CreateDbContextAsync();
+
+                var userExists = await db.Users.AnyAsync(u => u.Id == userId && u.IsActive);
+                if (!userExists)
+                {
+                    context.Fail("User no longer exists or is inactive.");
+                }
             }
         };
     });
@@ -79,21 +112,28 @@ var app = builder.Build();
 // Aspire Default Endpoints (Health Checks)
 app.MapDefaultEndpoints();
 
-// Migrations anwenden
+// Migrations anwenden und Testdaten seeden (nur wenn die Datenbank leer ist)
 using (var scope = app.Services.CreateScope())
 {
     var db = scope.ServiceProvider.GetRequiredService<SlipItInDbContext>();
     db.Database.Migrate();
+    await DbSeeder.SeedAsync(db);
 }
 
 // Configure the HTTP request pipeline.
 if (app.Environment.IsDevelopment())
 {
     app.MapOpenApi();
-    app.UseCors("AllowAll");
 }
 
-app.UseHttpsRedirection();
+app.UseCors("AllowAll");
+
+// Beim Emulator/geräteübergreifenden Zugriff würde die HTTPS-Umleitung
+// den Client auf eine nicht vertrauenswürdige Dev-Zertifikats-URL schicken.
+if (!app.Environment.IsDevelopment())
+{
+    app.UseHttpsRedirection();
+}
 app.UseAuthentication();
 app.UseAuthorization();
 

SlipItIn.Server/Services/GameService.cs

@@ -2,6 +2,7 @@ using Microsoft.EntityFrameworkCore;
 using SlipItIn.Server.Data;
 using SlipItIn.Shared.DTOs;
 using SlipItIn.Shared.Models;
+using System.Security.Cryptography;
 
 namespace SlipItIn.Server.Services;
 
@@ -21,7 +22,7 @@ public class GameService : IGameService
         using var context = _contextFactory.CreateDbContext();
 
         var host = await context.Users.FirstOrDefaultAsync(u => u.Id == hostUserId) ?? throw new InvalidOperationException("Host not found");
-        var lobbyCode = GenerateLobbyCode();
+        var lobbyCode = await GenerateUniqueLobbyCodeAsync(context);
         var game = new Game
         {
             LobbyCode = lobbyCode,
@@ -70,7 +71,16 @@ public class GameService : IGameService
     {
         using var context = _contextFactory.CreateDbContext();
 
-        var game = await context.Games.FirstOrDefaultAsync(g => g.Id == gameId) ?? throw new InvalidOperationException("Game not found");
+        var game = await context.Games
+            .Include(g => g.Players)
+            .FirstOrDefaultAsync(g => g.Id == gameId) ?? throw new InvalidOperationException("Game not found");
+
+        if (game.Status != GameStatus.Lobby)
+            throw new InvalidOperationException("Game has already started or ended");
+
+        if (game.Players.Count < 2)
+            throw new InvalidOperationException("At least 2 players are required to start the game");
+
         game.Status = GameStatus.InProgress;
         game.StartedAt = DateTime.UtcNow;
 
@@ -85,12 +95,16 @@ public class GameService : IGameService
     {
         using var context = _contextFactory.CreateDbContext();
 
-        var player = await context.Players.FirstOrDefaultAsync(p => p.Id == playerId) ?? throw new InvalidOperationException("Player not found");
+        var game = await context.Games.FirstOrDefaultAsync(g => g.Id == gameId) ?? throw new InvalidOperationException("Game not found");
+        if (game.Status != GameStatus.Lobby)
+            throw new InvalidOperationException("Game is not in lobby status");
+
+        var player = await context.Players.FirstOrDefaultAsync(p => p.Id == playerId && p.GameId == gameId)
+            ?? throw new InvalidOperationException("Player not found in this game");
         player.IsReady = true;
         await context.SaveChangesAsync();
 
-        return await context.Games.FirstOrDefaultAsync(g => g.Id == gameId) 
-            ?? throw new InvalidOperationException("Game not found");
+        return game;
     }
 
     public async Task<List<PlayerCard>> DealCardsAsync(int gameId)
@@ -108,7 +122,7 @@ public class GameService : IGameService
 
         foreach (var player in players)
         {
-            var selectedPhrases = allPhrases.OrderBy(_ => Random.Shared.Next()).Take(5);
+            var selectedPhrases = allPhrases.OrderBy(_ => RandomNumberGenerator.GetInt32(int.MaxValue)).Take(5);
 
             foreach (var phrase in selectedPhrases)
             {
@@ -125,6 +139,7 @@ public class GameService : IGameService
         }
 
         currentRound.Status = RoundStatus.Active;
+        currentRound.StartedAt = DateTime.UtcNow;
         await context.SaveChangesAsync();
 
         return dealtCards;
@@ -134,10 +149,18 @@ public class GameService : IGameService
     {
         using var context = _contextFactory.CreateDbContext();
 
+        var game = await context.Games.FirstOrDefaultAsync(g => g.Id == gameId) ?? throw new InvalidOperationException("Game not found");
+        if (game.Status != GameStatus.InProgress)
+            throw new InvalidOperationException("Game is not in progress");
+
         var card = await context.PlayerCards
-            .Include(pc => pc.Player)
+            .Include(pc => pc.GameRound)
             .FirstOrDefaultAsync(pc => pc.Id == cardId) ?? throw new InvalidOperationException("Card not found");
+
         if (card.PlayerId != playerId) throw new UnauthorizedAccessException("Card does not belong to player");
+        if (card.GameRound.GameId != gameId) throw new InvalidOperationException("Card does not belong to this game");
+        if (card.GameRound.Status != RoundStatus.Active) throw new InvalidOperationException("Round is not active");
+        if (card.IsUsed) throw new InvalidOperationException("Card has already been used");
 
         card.IsUsed = true;
         await context.SaveChangesAsync();
@@ -149,13 +172,29 @@ public class GameService : IGameService
     {
         using var context = _contextFactory.CreateDbContext();
 
-        var targetCard = await context.PlayerCards.FirstOrDefaultAsync(pc => pc.Id == targetCardId) ?? throw new InvalidOperationException("Target card not found");
-
         var currentRound = await context.GameRounds
             .Where(gr => gr.GameId == gameId && gr.Status == RoundStatus.Active)
             .FirstOrDefaultAsync() ?? throw new InvalidOperationException("No active round found");
 
-        if (currentRound == null) throw new InvalidOperationException("No active round found");
+        var challengerBelongsToGame = await context.Players
+            .AnyAsync(p => p.Id == challengingPlayerId && p.GameId == gameId);
+        if (!challengerBelongsToGame)
+            throw new UnauthorizedAccessException("Challenger does not belong to this game");
+
+        var targetCard = await context.PlayerCards
+            .FirstOrDefaultAsync(pc => pc.Id == targetCardId) ?? throw new InvalidOperationException("Target card not found");
+
+        if (targetCard.GameRoundId != currentRound.Id)
+            throw new InvalidOperationException("Card does not belong to the active round");
+        if (targetCard.PlayerId == challengingPlayerId)
+            throw new InvalidOperationException("Cannot challenge your own card");
+        if (!targetCard.IsUsed)
+            throw new InvalidOperationException("Card has not been played yet");
+
+        var pendingExists = await context.SlipChallenges
+            .AnyAsync(c => c.TargetCardId == targetCardId && c.Status == ChallengeStatus.Pending);
+        if (pendingExists)
+            throw new InvalidOperationException("A challenge for this card is already pending");
 
         var challenge = new SlipChallenge
         {
@@ -179,19 +218,30 @@ public class GameService : IGameService
         var challenge = await context.SlipChallenges
             .Include(sc => sc.GameRound)
             .Include(sc => sc.TargetCard)
+            .Include(sc => sc.ChallengingPlayer)
+            .Include(sc => sc.TargetPlayer)
             .FirstOrDefaultAsync(sc => sc.Id == challengeId) ?? throw new InvalidOperationException("Challenge not found");
 
-        // approved = Beschuldigung stimmt (Phrase war falsch)
-        // rejected = Beschuldigung stimmt nicht (Phrase war richtig)
+        if (challenge.Status != ChallengeStatus.Pending)
+            throw new InvalidOperationException("Challenge has already been resolved");
 
-        if (!approved)
+        // approved = Beschuldigung stimmt (Phrase war ein unberechtigtes SlipIn des Beschuldigten)
+        // rejected = Beschuldigung stimmt nicht (Phrase wurde regelkonform gespielt)
+
+        if (approved)
         {
-            // FALSCHE BESCHULDIGUNG: Beschuldiger erhält die Phrase des Beschuldigten
-            var targetCard = challenge.TargetCard;
-            targetCard.PlayerId = challenge.ChallengingPlayerId;
-            context.PlayerCards.Update(targetCard);
+            // Berechtigte Beschuldigung: Beschuldigter muss die Phrase an den Beschuldiger abgeben
+            challenge.TargetCard.PlayerId = challenge.ChallengingPlayerId;
+            challenge.ChallengingPlayer.Score += 1;
+            challenge.TargetPlayer.FailedSlips += 1;
+        }
+        else
+        {
+            // Falsche Beschuldigung: Phrase bleibt beim Beschuldigten
+            challenge.TargetPlayer.SuccessfulSlips += 1;
+            challenge.TargetPlayer.Score += 1;
+            challenge.ChallengingPlayer.FailedSlips += 1;
         }
-        // Wenn approved: Phrase bleibt bei Beschuldigtem (= Phrase war tatsächlich ein SlipIn)
 
         challenge.Status = approved ? ChallengeStatus.Approved : ChallengeStatus.Rejected;
         challenge.ResolvedAt = DateTime.UtcNow;
@@ -218,7 +268,7 @@ public class GameService : IGameService
             Username = p.User.Username,
             Score = p.Score,
             IsReady = p.IsReady,
-            CardCount = p.Cards.Count // Nur Anzahl, nicht die Karten selbst!
+            CardCount = p.Cards.Count(c => !c.IsUsed) // Nur Anzahl, nicht die Karten selbst!
         }).ToList();
 
         var currentRound = game.Rounds
@@ -249,9 +299,17 @@ public class GameService : IGameService
     {
         using var context = _contextFactory.CreateDbContext();
 
+        // Nur Karten der aktuell aktiven Runde zurückgeben — sonst wächst die Hand
+        // über Runden hinweg unbegrenzt und enthält veraltete Karten.
+        var activeRoundIds = await context.GameRounds
+            .Where(gr => gr.Status == RoundStatus.Active &&
+                         gr.Game.Players.Any(p => p.Id == playerId))
+            .Select(gr => gr.Id)
+            .ToListAsync();
+
         var cards = await context.PlayerCards
             .Include(pc => pc.Phrase)
-            .Where(pc => pc.PlayerId == playerId)
+            .Where(pc => pc.PlayerId == playerId && activeRoundIds.Contains(pc.GameRoundId))
             .Select(pc => new PlayerCardDto
             {
                 CardId = pc.Id,
@@ -275,11 +333,25 @@ public class GameService : IGameService
             ?? throw new InvalidOperationException("Game not found");
     }
 
-    private string GenerateLobbyCode()
+    private static string GenerateLobbyCode()
     {
         const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-        var code = new string([.. Enumerable.Range(0, 6).Select(_ => chars[Random.Shared.Next(chars.Length)])]);
+        var buffer = new char[6];
+        for (var i = 0; i < buffer.Length; i++)
+            buffer[i] = chars[RandomNumberGenerator.GetInt32(chars.Length)];
+        return new string(buffer);
+    }
 
-        return code;
+    private static async Task<string> GenerateUniqueLobbyCodeAsync(SlipItInDbContext context, int maxAttempts = 10)
+    {
+        for (var attempt = 0; attempt < maxAttempts; attempt++)
+        {
+            var code = GenerateLobbyCode();
+            var exists = await context.Games.AnyAsync(g => g.LobbyCode == code);
+            if (!exists)
+                return code;
+        }
+
+        throw new InvalidOperationException("Could not generate a unique lobby code");
     }
 }

SlipItIn.Server/SlipItIn.Server.csproj

@@ -7,14 +7,14 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Aspire.Npgsql" Version="13.4.6" />
-    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="10.0.10" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="10.0.10">
+    <PackageReference Include="Aspire.Npgsql" Version="13.5.2" />
+    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="10.0.11" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="10.0.11">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
 
-    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.10" />
+    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.11" />
     <PackageReference Include="BCrypt.Net-Next" Version="4.2.0" />
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="10.0.3" />
   </ItemGroup>

SlipItIn.Server/appsettings.Development.json

@@ -4,5 +4,8 @@
       "Default": "Information",
       "Microsoft.AspNetCore": "Warning"
     }
+  },
+  "Jwt": {
+    "Key": "DevOnlyKey-NotForProduction-ChangeMe-0123456789abcdef"
   }
 }

SlipItIn.Server/appsettings.json

@@ -7,11 +7,7 @@
     }
   },
   "AllowedHosts": "*",
-  "ConnectionStrings": {
-    "postgresdb": "Server=(localdb)\\postgres;Database=postgresdb"
-  },
   "Jwt": {
-    "Key": "YourSuperSecretKeyThatIsAtLeast32CharactersLong!",
     "Issuer": "SlipItInServer",
     "Audience": "SlipItInClient",
     "ExpirationMinutes": 1440

SlipItIn.ServiceDefaults/SlipItIn.ServiceDefaults.csproj

@@ -10,13 +10,13 @@
   <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
 
-    <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.ServiceDiscovery" Version="10.8.0" />
-    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.17.0" />
-    <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.17.0" />
-    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.17.0" />
-    <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.17.0" />
-    <PackageReference Include="OpenTelemetry.Instrumentation.Runtime" Version="1.17.0" />
+    <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.ServiceDiscovery" Version="10.9.0" />
+    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.18.0" />
+    <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.18.0" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.18.0" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.18.0" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.Runtime" Version="1.18.0" />
   </ItemGroup>
 
 </Project>

SlipItIn.Shared/SlipItIn.Shared.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="10.0.10" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="10.0.11" />
   </ItemGroup>
 
 </Project>

SlipItIn.slnx

@@ -1,13 +1,10 @@
 <Solution>
-  <Folder Name="/Projektmappenelemente/">
-    <File Path="Agents/Architecture.md" />
-    <File Path="Agents/ProjectPlan.md" />
-  </Folder>
-  <Project Path="SlipItIN.AppHost/SlipItIn.AppHost.csproj" />
+  <Project Path="SlipItIn.AppHost/SlipItIn.AppHost.csproj" />
+  <Project Path="SlipItIn.Server.Tests/SlipItIn.Server.Tests.csproj" />
   <Project Path="SlipItIn.Server/SlipItIn.Server.csproj" />
-  <Project Path="SlipItIN.ServiceDefaults/SlipItIn.ServiceDefaults.csproj" />
+  <Project Path="SlipItIn.ServiceDefaults/SlipItIn.ServiceDefaults.csproj" />
   <Project Path="SlipItIn.Shared/SlipItIn.Shared.csproj" />
-  <Project Path="SlipItIN/SlipItIn.csproj">
+  <Project Path="SlipItIn/SlipItIn.csproj">
     <Deploy Solution="Debug|*" />
   </Project>
 </Solution>

SlipItIn/App.xaml.cs

@@ -5,37 +5,82 @@ namespace SlipItIn;
 
 public partial class App : Application
 {
+	private readonly SemaphoreSlim _startupLock = new(1, 1);
+
 	public App()
 	{
 		InitializeComponent();
-		_ = InitializeAsync();
 	}
 
 	protected override Window CreateWindow(IActivationState? activationState)
 	{
 		var window = new Window(new AppShell());
+
+		window.Created += async (_, _) =>
+		{
+			await InitializeSafeAsync();
+		};
+
 		window.Resumed += async (_, _) =>
 		{
-			var gameStateService = ServiceHelper.GetRequiredService<IGameStateService>();
-			await gameStateService.ResyncAsync();
+			try
+			{
+				var gameStateService = ServiceHelper.GetRequiredService<IGameStateService>();
+				await gameStateService.ResyncAsync();
+			}
+			catch
+			{
+				// Resume darf nicht abstürzen; Sync-Status wurde bereits gemeldet.
+			}
 		};
+
 		return window;
 	}
 
-	private static async Task InitializeAsync()
+	private async Task InitializeSafeAsync()
 	{
-		var authSession = ServiceHelper.GetRequiredService<IAuthSessionService>();
-		var signalR = ServiceHelper.GetRequiredService<ISignalRService>();
-		var gameStateService = ServiceHelper.GetRequiredService<IGameStateService>();
+		if (!await _startupLock.WaitAsync(0))
+			return;
 
-		await authSession.InitializeAsync();
-		await gameStateService.InitializeAsync();
-
-		if (!string.IsNullOrWhiteSpace(authSession.AccessToken))
+		try
 		{
+			var authSession = ServiceHelper.GetRequiredService<IAuthSessionService>();
+			var signalR = ServiceHelper.GetRequiredService<ISignalRService>();
+			var gameStateService = ServiceHelper.GetRequiredService<IGameStateService>();
+			var apiService = ServiceHelper.GetRequiredService<IApiService>();
+
+			await authSession.InitializeAsync();
+			await gameStateService.InitializeAsync();
+
+			if (string.IsNullOrWhiteSpace(authSession.AccessToken))
+				return;
+
+			var sessionResult = await apiService.ValidateSessionAsync();
+			if (sessionResult == SessionValidationResult.NetworkError)
+			{
+				// Netzwerkfehler darf die lokale Session nicht zerstören.
+				return;
+			}
+
+			if (sessionResult == SessionValidationResult.Invalid)
+			{
+				await authSession.ClearSessionAsync();
+				await gameStateService.ClearLocalGameDataAsync();
+				await signalR.DisconnectAsync();
+				return;
+			}
+
 			var connected = await signalR.ConnectAsync(authSession.AccessToken);
 			if (connected)
 				await gameStateService.ResyncAsync();
 		}
+		catch
+		{
+			// Start darf nicht abstürzen, wenn Session/Netzwerk fehlschlägt.
+		}
+		finally
+		{
+			_startupLock.Release();
+		}
 	}
 }

SlipItIn/AppShell.xaml

@@ -3,22 +3,12 @@
     x:Class="SlipItIn.AppShell"
     xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
     xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-    xmlns:views="clr-namespace:SlipItIn.Views">
+    xmlns:views="clr-namespace:SlipItIn.Views"
+    FlyoutBehavior="Disabled">
 
-    <ShellContent 
-        Route="LoginPage" 
+    <ShellContent
+        Title="Login"
+        Route="LoginPage"
         ContentTemplate="{DataTemplate views:LoginPage}" />
 
-    <ShellContent 
-        Route="RegisterPage" 
-        ContentTemplate="{DataTemplate views:RegisterPage}" />
-
-    <ShellContent 
-        Route="LobbyPage" 
-        ContentTemplate="{DataTemplate views:LobbyPage}" />
-    
-    <ShellContent 
-        Route="GameBoardPage" 
-        ContentTemplate="{DataTemplate views:GameBoardPage}" />
-
 </Shell>

SlipItIn/AppShell.xaml.cs

@@ -7,5 +7,8 @@ public partial class AppShell : Shell
 	public AppShell()
 	{
 		InitializeComponent();
+		Routing.RegisterRoute(nameof(RegisterPage), typeof(RegisterPage));
+		Routing.RegisterRoute(nameof(LobbyPage), typeof(LobbyPage));
+		Routing.RegisterRoute(nameof(GameBoardPage), typeof(GameBoardPage));
 	}
 }

SlipItIn/Messages/SyncStateChangedMessage.cs

@@ -0,0 +1,12 @@
+using CommunityToolkit.Mvvm.Messaging.Messages;
+
+namespace SlipItIn.Messages;
+
+public sealed record SyncStateInfo(bool IsSyncing, string StatusText, int PendingActions);
+
+public class SyncStateChangedMessage : ValueChangedMessage<SyncStateInfo>
+{
+    public SyncStateChangedMessage(SyncStateInfo value) : base(value)
+    {
+    }
+}

SlipItIn/Models/QueuedGameAction.cs

@@ -5,4 +5,5 @@ public class QueuedGameAction
     public string Method { get; set; } = string.Empty;
     public string ArgumentsJson { get; set; } = "[]";
     public DateTime CreatedAtUtc { get; set; } = DateTime.UtcNow;
+    public int RetryCount { get; set; }
 }

SlipItIn/Platforms/Android/AndroidManifest.Debug.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="de.krampitz.slipitin">
+  <application
+      android:allowBackup="true"
+      android:icon="@mipmap/appicon"
+      android:supportsRtl="true"
+      android:label="Slip It In"
+      android:usesCleartextTraffic="true" />
+  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+  <uses-permission android:name="android.permission.INTERNET" />
+</manifest>

SlipItIn/Platforms/Android/AndroidManifest.Release.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="de.krampitz.slipitin">
+  <application
+      android:allowBackup="true"
+      android:icon="@mipmap/appicon"
+      android:supportsRtl="true"
+      android:label="Slip It In">
+  </application>
+  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+  <uses-permission android:name="android.permission.INTERNET" />
+</manifest>

SlipItIn/Platforms/Android/AndroidManifest.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="de.krampitz.slipitin">
-	<application android:allowBackup="true" android:icon="@mipmap/appicon" android:supportsRtl="true" android:label="Slip It In"></application>
-	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
-	<uses-permission android:name="android.permission.INTERNET" />
-</manifest>

SlipItIn/Services/ApiService.cs

@@ -28,6 +28,29 @@ public class ApiService : IApiService
     public Task<AuthResponseDto> LoginAsync(LoginRequestDto request, CancellationToken cancellationToken = default)
         => PostAuthAsync("api/auth/login", request, cancellationToken);
 
+    public async Task<SessionValidationResult> ValidateSessionAsync(CancellationToken cancellationToken = default)
+    {
+        if (string.IsNullOrWhiteSpace(_authSession.AccessToken))
+            return SessionValidationResult.Invalid;
+
+        try
+        {
+            AttachAuthHeader();
+            var response = await _httpClient.GetAsync("api/auth/me", cancellationToken);
+            return response.IsSuccessStatusCode
+                ? SessionValidationResult.Valid
+                : SessionValidationResult.Invalid;
+        }
+        catch (HttpRequestException)
+        {
+            return SessionValidationResult.NetworkError;
+        }
+        catch (TaskCanceledException)
+        {
+            return SessionValidationResult.NetworkError;
+        }
+    }
+
     public Task LogoutAsync() => _authSession.ClearSessionAsync();
 
     private async Task<AuthResponseDto> PostAuthAsync<TRequest>(string endpoint, TRequest request, CancellationToken cancellationToken)

SlipItIn/Services/AppConfigurationService.cs

@@ -4,9 +4,20 @@ namespace SlipItIn.Services;
 
 public class AppConfigurationService : IAppConfigurationService
 {
+    private const string ApiBaseUrlPreferenceKey = "api_base_url";
     private const string DefaultApiBaseUrl = "https://localhost:7274";
+    private const string AndroidEmulatorApiBaseUrl = "http://10.0.2.2:5234";
 
-    public string ApiBaseUrl => DefaultApiBaseUrl;
+    public string ApiBaseUrl => Preferences.Default
+        .Get(ApiBaseUrlPreferenceKey, GetPlatformDefaultApiBaseUrl())
+        .TrimEnd('/');
 
-    public string HubUrl => $"{DefaultApiBaseUrl.TrimEnd('/')}/hubs/game";
+    public string HubUrl => $"{ApiBaseUrl}/hubs/game";
+
+    private static string GetPlatformDefaultApiBaseUrl()
+    {
+        return DeviceInfo.Platform == DevicePlatform.Android
+            ? AndroidEmulatorApiBaseUrl
+            : DefaultApiBaseUrl;
+    }
 }

SlipItIn/Services/GameStateService.cs

@@ -12,6 +12,7 @@ public class GameStateService : IGameStateService
     private readonly ISignalRService _signalR;
     private readonly ILocalStorageService _localStorage;
     private readonly IMessenger _messenger;
+    private readonly SemaphoreSlim _syncLock = new(1, 1);
 
     private readonly List<QueuedGameAction> _queuedActions = [];
 
@@ -27,21 +28,21 @@ public class GameStateService : IGameStateService
 
         _signalR.LobbyCreated += (_, value) => _messenger.Send(new LobbyCreatedMessage(value));
 
-        _signalR.GameStateUpdated += async (_, state) =>
+        _signalR.GameStateUpdated += (_, state) => RunSafeBridge(async () =>
         {
             CurrentGameState = state;
             await _localStorage.SaveGameStateAsync(state);
             _messenger.Send(new GameStateChangedMessage(state));
-        };
+        });
 
         _signalR.GameStarted += (_, gameId) => _messenger.Send(new GameStartedMessage(gameId));
 
-        _signalR.PlayerHandUpdated += async (_, hand) =>
+        _signalR.PlayerHandUpdated += (_, hand) => RunSafeBridge(async () =>
         {
             CurrentPlayerHand = hand;
             await _localStorage.SavePlayerHandAsync(hand);
             _messenger.Send(new PlayerHandChangedMessage(hand));
-        };
+        });
 
         _signalR.ChallengeReceived += (_, challenge) =>
         {
@@ -50,7 +51,26 @@ public class GameStateService : IGameStateService
         };
 
         _signalR.ErrorReceived += (_, error) => _messenger.Send(new ErrorOccurredMessage(error));
-        _signalR.ConnectionStateChanged += (_, connected) => _messenger.Send(new ConnectionStateChangedMessage(connected));
+        _signalR.ConnectionStateChanged += (_, connected) => RunSafeBridge(async () =>
+        {
+            _messenger.Send(new ConnectionStateChangedMessage(connected));
+            if (!connected)
+                return;
+
+            await ResyncAsync();
+        });
+    }
+
+    private async void RunSafeBridge(Func<Task> action)
+    {
+        try
+        {
+            await action();
+        }
+        catch (Exception ex)
+        {
+            _messenger.Send(new ErrorOccurredMessage($"Hintergrundfehler: {ex.Message}"));
+        }
     }
 
     public async Task InitializeAsync()
@@ -67,14 +87,32 @@ public class GameStateService : IGameStateService
 
         if (CurrentPlayerHand is not null)
             _messenger.Send(new PlayerHandChangedMessage(CurrentPlayerHand));
+
+        PublishSyncState(false, "Bereit", _queuedActions.Count);
     }
 
     public async Task ResyncAsync()
     {
-        if (CurrentGameState?.GameId > 0 && _signalR.IsConnected)
-            await _signalR.RequestGameStateAsync(CurrentGameState.GameId);
+        await _syncLock.WaitAsync();
+        try
+        {
+            PublishSyncState(true, "Syncing...", _queuedActions.Count);
 
-        await FlushQueuedActionsAsync();
+            if (CurrentGameState?.GameId > 0 && _signalR.IsConnected)
+                await _signalR.RequestGameStateAsync(CurrentGameState.GameId);
+
+            await FlushQueuedActionsCoreAsync();
+            PublishSyncState(false, "Synchronisiert", _queuedActions.Count);
+        }
+        catch
+        {
+            PublishSyncState(false, "Sync fehlgeschlagen", _queuedActions.Count);
+            throw;
+        }
+        finally
+        {
+            _syncLock.Release();
+        }
     }
 
     public async Task EnqueueActionAsync(string method, params object[] arguments)
@@ -88,21 +126,22 @@ public class GameStateService : IGameStateService
 
         _queuedActions.Add(action);
         await _localStorage.SaveQueuedActionsAsync(_queuedActions);
+        PublishSyncState(false, "Offline-Aktion gespeichert", _queuedActions.Count);
     }
 
     public async Task FlushQueuedActionsAsync()
     {
-        if (!_signalR.IsConnected || _queuedActions.Count == 0)
-            return;
-
-        var snapshot = _queuedActions.ToList();
-        foreach (var action in snapshot)
+        await _syncLock.WaitAsync();
+        try
         {
-            await _signalR.SendQueuedActionAsync(action);
-            _queuedActions.Remove(action);
+            PublishSyncState(true, "Warteschlange wird gesendet...", _queuedActions.Count);
+            await FlushQueuedActionsCoreAsync();
+            PublishSyncState(false, "Warteschlange synchronisiert", _queuedActions.Count);
+        }
+        finally
+        {
+            _syncLock.Release();
         }
-
-        await _localStorage.SaveQueuedActionsAsync(_queuedActions);
     }
 
     public async Task ClearLocalGameDataAsync()
@@ -115,5 +154,52 @@ public class GameStateService : IGameStateService
         await _localStorage.ClearGameStateAsync();
         await _localStorage.ClearPlayerHandAsync();
         await _localStorage.ClearQueuedActionsAsync();
+
+        PublishSyncState(false, "Bereit", 0);
+    }
+
+    private const int MaxQueueRetries = 3;
+
+    private async Task FlushQueuedActionsCoreAsync()
+    {
+        if (!_signalR.IsConnected || _queuedActions.Count == 0)
+            return;
+
+        var snapshot = _queuedActions.ToList();
+        var poisoned = new List<QueuedGameAction>();
+
+        foreach (var action in snapshot)
+        {
+            try
+            {
+                await _signalR.SendQueuedActionAsync(action);
+                _queuedActions.Remove(action);
+                PublishSyncState(true, "Warteschlange wird gesendet...", _queuedActions.Count);
+            }
+            catch (Exception ex)
+            {
+                action.RetryCount++;
+                if (action.RetryCount >= MaxQueueRetries)
+                {
+                    poisoned.Add(action);
+                    _messenger.Send(new ErrorOccurredMessage($"Queue-Aktion verworfen ({action.Method}): {ex.Message}"));
+                }
+                else
+                {
+                    _messenger.Send(new ErrorOccurredMessage($"Queue-Aktion fehlgeschlagen ({action.Method}): {ex.Message}"));
+                    break; // Bei transienten Fehlern den Rest der Queue nicht blockieren
+                }
+            }
+        }
+
+        foreach (var item in poisoned)
+            _queuedActions.Remove(item);
+
+        await _localStorage.SaveQueuedActionsAsync(_queuedActions);
+    }
+
+    private void PublishSyncState(bool isSyncing, string statusText, int pendingActions)
+    {
+        _messenger.Send(new SyncStateChangedMessage(new SyncStateInfo(isSyncing, statusText, pendingActions)));
     }
 }

SlipItIn/Services/Interfaces/IApiService.cs

@@ -2,9 +2,17 @@ using SlipItIn.Shared.DTOs;
 
 namespace SlipItIn.Services.Interfaces;
 
+public enum SessionValidationResult
+{
+    Valid,
+    Invalid,
+    NetworkError
+}
+
 public interface IApiService
 {
     Task<AuthResponseDto> RegisterAsync(RegisterRequestDto request, CancellationToken cancellationToken = default);
     Task<AuthResponseDto> LoginAsync(LoginRequestDto request, CancellationToken cancellationToken = default);
+    Task<SessionValidationResult> ValidateSessionAsync(CancellationToken cancellationToken = default);
     Task LogoutAsync();
 }

SlipItIn/Services/SignalRService.cs

@@ -1,21 +1,25 @@
 using System.Text.Json;
 using Microsoft.AspNetCore.SignalR.Client;
+using Microsoft.Extensions.DependencyInjection;
 using SlipItIn.Models;
 using SlipItIn.Services.Interfaces;
 using SlipItIn.Shared.DTOs;
 
 namespace SlipItIn.Services;
 
-public class SignalRService : ISignalRService
+public class SignalRService : ISignalRService, IAsyncDisposable
 {
     private readonly IAppConfigurationService _configuration;
     private readonly IAuthSessionService _authSession;
+    private readonly IServiceProvider _serviceProvider;
+    private readonly SemaphoreSlim _connectLock = new(1, 1);
     private HubConnection? _hubConnection;
 
-    public SignalRService(IAppConfigurationService configuration, IAuthSessionService authSession)
+    public SignalRService(IAppConfigurationService configuration, IAuthSessionService authSession, IServiceProvider serviceProvider)
     {
         _configuration = configuration;
         _authSession = authSession;
+        _serviceProvider = serviceProvider;
     }
 
     public bool IsConnected => _hubConnection?.State == HubConnectionState.Connected;
@@ -33,31 +37,76 @@ public class SignalRService : ISignalRService
         if (IsConnected)
             return true;
 
-        EnsureConnection(token);
-
-        if (_hubConnection is null)
-            return false;
-
+        await _connectLock.WaitAsync(cancellationToken);
         try
         {
-            await _hubConnection.StartAsync(cancellationToken);
-            ConnectionStateChanged?.Invoke(this, true);
-            return true;
+            if (IsConnected)
+                return true;
+
+            // Bestehende (möglicherweise tote) Verbindung vollständig entsorgen,
+            // damit der AccessTokenProvider keinen veralteten Token-Closure verwendet.
+            if (_hubConnection is not null)
+            {
+                try
+                {
+                    if (_hubConnection.State is HubConnectionState.Connected or HubConnectionState.Connecting or HubConnectionState.Reconnecting)
+                        await _hubConnection.StopAsync(cancellationToken);
+                }
+                catch
+                {
+                    // Best effort; Dispose folgt trotzdem.
+                }
+
+                await _hubConnection.DisposeAsync();
+                _hubConnection = null;
+            }
+
+            EnsureConnection(token);
+
+            if (_hubConnection is null)
+                return false;
+
+            ConnectionStateChanged?.Invoke(this, false);
+
+            try
+            {
+                await _hubConnection.StartAsync(cancellationToken);
+                ConnectionStateChanged?.Invoke(this, true);
+                return true;
+            }
+            catch (Exception ex)
+            {
+                ConnectionStateChanged?.Invoke(this, false);
+                ErrorReceived?.Invoke(this, $"SignalR-Verbindung fehlgeschlagen: {ex.Message}");
+                return false;
+            }
         }
-        catch (Exception ex)
+        finally
         {
-            ErrorReceived?.Invoke(this, $"SignalR-Verbindung fehlgeschlagen: {ex.Message}");
-            return false;
+            _connectLock.Release();
         }
     }
 
     public async Task DisconnectAsync()
     {
-        if (_hubConnection is null)
-            return;
+        await _connectLock.WaitAsync();
+        try
+        {
+            if (_hubConnection is null)
+                return;
 
-        await _hubConnection.StopAsync();
-        ConnectionStateChanged?.Invoke(this, false);
+            if (_hubConnection.State is HubConnectionState.Connected or HubConnectionState.Connecting or HubConnectionState.Reconnecting)
+                await _hubConnection.StopAsync();
+
+            await _hubConnection.DisposeAsync();
+            _hubConnection = null;
+
+            ConnectionStateChanged?.Invoke(this, false);
+        }
+        finally
+        {
+            _connectLock.Release();
+        }
     }
 
     public Task CreateLobbyAsync() => InvokeAsync("CreateLobby");
@@ -82,7 +131,7 @@ public class SignalRService : ISignalRService
     public async Task SendQueuedActionAsync(QueuedGameAction action)
     {
         if (_hubConnection is null)
-            return;
+            throw new InvalidOperationException("Keine aktive SignalR-Verbindung.");
 
         object?[] args;
         try
@@ -90,11 +139,11 @@ public class SignalRService : ISignalRService
             var doc = JsonDocument.Parse(action.ArgumentsJson);
             args = doc.RootElement.ValueKind == JsonValueKind.Array
                 ? doc.RootElement.EnumerateArray().Select(ToObject).ToArray()
-                : [];
+                : throw new InvalidOperationException($"Ungültige Queue-Aktion: {action.ArgumentsJson}");
         }
-        catch
+        catch (JsonException ex)
         {
-            args = [];
+            throw new InvalidOperationException($"Queue-Aktion '{action.Method}' ist beschädigt.", ex);
         }
 
         await InvokeAsync(action.Method, args);
@@ -108,11 +157,18 @@ public class SignalRService : ISignalRService
         _hubConnection = new HubConnectionBuilder()
             .WithUrl(_configuration.HubUrl, options =>
             {
-                options.AccessTokenProvider = () => Task.FromResult<string?>(token);
+                // Token immer zur Laufzeit aus der Session lesen — nie den Startwert cachen.
+                options.AccessTokenProvider = () => Task.FromResult(_authSession.AccessToken);
             })
             .WithAutomaticReconnect([TimeSpan.Zero, TimeSpan.FromSeconds(2), TimeSpan.FromSeconds(10), TimeSpan.FromSeconds(30)])
             .Build();
 
+        _hubConnection.Reconnecting += _ =>
+        {
+            ConnectionStateChanged?.Invoke(this, false);
+            return Task.CompletedTask;
+        };
+
         _hubConnection.Closed += _ =>
         {
             ConnectionStateChanged?.Invoke(this, false);
@@ -144,6 +200,13 @@ public class SignalRService : ISignalRService
         _hubConnection.On<PlayerHandDto>("PlayerHandUpdated", dto => PlayerHandUpdated?.Invoke(this, dto));
         _hubConnection.On<SlipChallengeDto>("ChallengeReceived", dto => ChallengeReceived?.Invoke(this, dto));
 
+        // Server-Broadcasts nach Slip/Challenge/Resolve, damit die UI auch ohne
+        // vollständiges GameState-Update reagieren kann.
+        _hubConnection.On<JsonElement>("SlipSubmitted", _ => RequestCurrentGameStateSafe());
+        _hubConnection.On<JsonElement>("SlipChallenged", _ => RequestCurrentGameStateSafe());
+        _hubConnection.On<JsonElement>("ChallengeResolved", _ => RequestCurrentGameStateSafe());
+        _hubConnection.On<JsonElement>("CardsDealt", _ => RequestCurrentGameStateSafe());
+
         _hubConnection.On<JsonElement>("Error", payload =>
         {
             var message = payload.TryGetProperty("message", out var msgElement)
@@ -153,6 +216,26 @@ public class SignalRService : ISignalRService
         });
     }
 
+    private void RequestCurrentGameStateSafe()
+    {
+        _ = Task.Run(async () =>
+        {
+            try
+            {
+                // Lazy über ServiceProvider auflösen, um eine zirkuläre Abhängigkeit
+                // SignalRService ↔ GameStateService zu vermeiden.
+                var gameStateService = _serviceProvider.GetService<IGameStateService>();
+                var gameState = gameStateService?.CurrentGameState;
+                if (gameState?.GameId > 0 && IsConnected)
+                    await RequestGameStateAsync(gameState.GameId);
+            }
+            catch
+            {
+                // Hintergrund-Refresh darf nicht abstürzen.
+            }
+        });
+    }
+
     private async Task InvokeAsync(string method, params object?[] args)
     {
         if (_hubConnection is null || _hubConnection.State != HubConnectionState.Connected)
@@ -175,4 +258,10 @@ public class SignalRService : ISignalRService
             _ => element.GetRawText()
         };
     }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_hubConnection is not null)
+            await _hubConnection.DisposeAsync();
+    }
 }

SlipItIn/SlipItIn.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
 	<PropertyGroup>
 		<TargetFrameworks>net10.0-android</TargetFrameworks>
@@ -48,35 +48,11 @@
 		<TargetPlatformMinVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.17763.0</TargetPlatformMinVersion>
 	</PropertyGroup>
 
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net10.0-android|AnyCPU'">
+	<PropertyGroup Condition="'$(Configuration)'=='Debug'">
 	  <ApplicationTitle>SlipItIn</ApplicationTitle>
 	</PropertyGroup>
 
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net10.0-ios|AnyCPU'">
-	  <ApplicationTitle>SlipItIn</ApplicationTitle>
-	</PropertyGroup>
-
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net10.0-maccatalyst|AnyCPU'">
-	  <ApplicationTitle>SlipItIn</ApplicationTitle>
-	</PropertyGroup>
-
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|net10.0-windows10.0.19041.0|AnyCPU'">
-	  <ApplicationTitle>SlipItIn</ApplicationTitle>
-	</PropertyGroup>
-
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net10.0-android|AnyCPU'">
-	  <ApplicationTitle>SlipItIn</ApplicationTitle>
-	</PropertyGroup>
-
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net10.0-ios|AnyCPU'">
-	  <ApplicationTitle>SlipItIn</ApplicationTitle>
-	</PropertyGroup>
-
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net10.0-maccatalyst|AnyCPU'">
-	  <ApplicationTitle>SlipItIn</ApplicationTitle>
-	</PropertyGroup>
-
-	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Release|net10.0-windows10.0.19041.0|AnyCPU'">
+	<PropertyGroup Condition="'$(Configuration)'=='Release'">
 	  <ApplicationTitle>SlipItIn</ApplicationTitle>
 	</PropertyGroup>
 
@@ -89,7 +65,6 @@
 
 		<!-- Images -->
 		<MauiImage Include="Resources\Images\*" />
-		<MauiImage Update="Resources\Images\dotnet_bot.png" Resize="True" BaseSize="300,185" />
 		
 		<!-- Custom Fonts -->
 		<MauiFont Include="Resources\Fonts\*" />
@@ -99,10 +74,10 @@
 	</ItemGroup>
 
 	<ItemGroup>
-		<PackageReference Include="Microsoft.Maui.Controls" Version="10.0.90" />
+		<PackageReference Include="Microsoft.Maui.Controls" Version="10.0.100" />
 		<PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="11.0.0-preview.6.26359.118" />
-		<PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.0" />
-		<PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="10.0.10" />
+		<PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.2" />
+		<PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="10.0.11" />
 	</ItemGroup>
 
 	<ItemGroup>
@@ -121,4 +96,12 @@
 	  </MauiXaml>
 	</ItemGroup>
 
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)'=='Debug|net10.0-android'">
+    <AndroidManifest>Platforms\Android\AndroidManifest.Debug.xml</AndroidManifest>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)'=='Release|net10.0-android'">
+    <AndroidManifest>Platforms\Android\AndroidManifest.Release.xml</AndroidManifest>
+  </PropertyGroup>
+
 </Project>

SlipItIn/ViewModels/GameBoardViewModel.cs

@@ -12,11 +12,15 @@ public partial class GameBoardViewModel : BaseViewModel,
     IRecipient<GameStateChangedMessage>,
     IRecipient<PlayerHandChangedMessage>,
     IRecipient<ChallengeReceivedMessage>,
-    IRecipient<ErrorOccurredMessage>
+    IRecipient<ErrorOccurredMessage>,
+    IRecipient<SyncStateChangedMessage>,
+    IRecipient<ConnectionStateChangedMessage>
 {
     private readonly ISignalRService _signalR;
     private readonly IGameStateService _gameStateService;
     private readonly IAuthSessionService _authSession;
+    private readonly IDispatcherTimer? _roundTimer;
+    private DateTime _lastStateUtc = DateTime.UtcNow;
 
     [ObservableProperty]
     private int gameId;
@@ -33,6 +37,18 @@ public partial class GameBoardViewModel : BaseViewModel,
     [ObservableProperty]
     private SlipChallengeDto? pendingChallenge;
 
+    [ObservableProperty]
+    private bool isConnected;
+
+    [ObservableProperty]
+    private bool isSyncing;
+
+    [ObservableProperty]
+    private string syncStatusText = "Bereit";
+
+    [ObservableProperty]
+    private int pendingSyncActions;
+
     public ObservableCollection<PlayerCardDto> MyCards { get; } = [];
     public ObservableCollection<PlayerInfoDto> OtherPlayers { get; } = [];
 
@@ -42,8 +58,28 @@ public partial class GameBoardViewModel : BaseViewModel,
         _gameStateService = gameStateService;
         _authSession = authSession;
 
-        WeakReferenceMessenger.Default.RegisterAll(this);
+        IsConnected = _signalR.IsConnected;
         IsActive = true;
+
+        if (Application.Current?.Dispatcher is { } dispatcher)
+        {
+            _roundTimer = dispatcher.CreateTimer();
+            _roundTimer.Interval = TimeSpan.FromSeconds(1);
+            _roundTimer.Tick += OnRoundTimerTick;
+        }
+    }
+
+    private void OnRoundTimerTick(object? sender, EventArgs e)
+    {
+        if (RoundTimeRemaining <= 0)
+            return;
+
+        var elapsed = (int)(DateTime.UtcNow - _lastStateUtc).TotalSeconds;
+        if (elapsed > 0)
+        {
+            RoundTimeRemaining = Math.Max(0, RoundTimeRemaining - elapsed);
+            _lastStateUtc = DateTime.UtcNow;
+        }
     }
 
     [RelayCommand]
@@ -109,9 +145,22 @@ public partial class GameBoardViewModel : BaseViewModel,
         if (PendingChallenge is null)
             return;
 
-        await _signalR.ResolveChallengeAsync(PendingChallenge.ChallengeId, true);
+        var challengeId = PendingChallenge.ChallengeId;
         PendingChallenge = null;
         IsChallengeVisible = false;
+
+        await RunSafeAsync(async () =>
+        {
+            if (_signalR.IsConnected)
+            {
+                await _signalR.ResolveChallengeAsync(challengeId, true);
+            }
+            else
+            {
+                await _gameStateService.EnqueueActionAsync("ResolveChallenge", challengeId, true);
+                StatusMessage = "Offline: Antwort wurde zwischengespeichert.";
+            }
+        });
     }
 
     [RelayCommand]
@@ -120,9 +169,22 @@ public partial class GameBoardViewModel : BaseViewModel,
         if (PendingChallenge is null)
             return;
 
-        await _signalR.ResolveChallengeAsync(PendingChallenge.ChallengeId, false);
+        var challengeId = PendingChallenge.ChallengeId;
         PendingChallenge = null;
         IsChallengeVisible = false;
+
+        await RunSafeAsync(async () =>
+        {
+            if (_signalR.IsConnected)
+            {
+                await _signalR.ResolveChallengeAsync(challengeId, false);
+            }
+            else
+            {
+                await _gameStateService.EnqueueActionAsync("ResolveChallenge", challengeId, false);
+                StatusMessage = "Offline: Antwort wurde zwischengespeichert.";
+            }
+        });
     }
 
     public void Receive(GameStateChangedMessage message)
@@ -132,6 +194,7 @@ public partial class GameBoardViewModel : BaseViewModel,
             GameId = message.Value.GameId;
             CurrentRound = message.Value.CurrentRound;
             RoundTimeRemaining = message.Value.RoundTimeRemaining;
+            _lastStateUtc = DateTime.UtcNow;
 
             var me = _authSession.CurrentUser?.Username;
             var others = message.Value.Players
@@ -156,15 +219,36 @@ public partial class GameBoardViewModel : BaseViewModel,
 
     public void Receive(ChallengeReceivedMessage message)
     {
-        PendingChallenge = message.Value;
-        IsChallengeVisible = true;
+        MainThread.BeginInvokeOnMainThread(() =>
+        {
+            PendingChallenge = message.Value;
+            IsChallengeVisible = true;
+        });
     }
 
     public void Receive(ErrorOccurredMessage message)
     {
-        StatusMessage = message.Value;
+        MainThread.BeginInvokeOnMainThread(() => StatusMessage = message.Value);
     }
 
+    public void Receive(SyncStateChangedMessage message)
+    {
+        MainThread.BeginInvokeOnMainThread(() =>
+        {
+            IsSyncing = message.Value.IsSyncing;
+            SyncStatusText = message.Value.StatusText;
+            PendingSyncActions = message.Value.PendingActions;
+        });
+    }
+
+    public void Receive(ConnectionStateChangedMessage message)
+    {
+        MainThread.BeginInvokeOnMainThread(() => IsConnected = message.Value);
+    }
+
+    public void StartRoundTimer() => _roundTimer?.Start();
+    public void StopRoundTimer() => _roundTimer?.Stop();
+
     private int GetCurrentPlayerId()
     {
         var username = _authSession.CurrentUser?.Username;

SlipItIn/ViewModels/LobbyViewModel.cs

@@ -13,7 +13,8 @@ public partial class LobbyViewModel : BaseViewModel,
     IRecipient<LobbyCreatedMessage>,
     IRecipient<GameStartedMessage>,
     IRecipient<ErrorOccurredMessage>,
-    IRecipient<ConnectionStateChangedMessage>
+    IRecipient<ConnectionStateChangedMessage>,
+    IRecipient<SyncStateChangedMessage>
 {
     private readonly ISignalRService _signalR;
     private readonly IGameStateService _gameStateService;
@@ -32,6 +33,15 @@ public partial class LobbyViewModel : BaseViewModel,
     [ObservableProperty]
     private bool isConnected;
 
+    [ObservableProperty]
+    private bool isSyncing;
+
+    [ObservableProperty]
+    private string syncStatusText = "Bereit";
+
+    [ObservableProperty]
+    private int pendingSyncActions;
+
     public ObservableCollection<PlayerInfoDto> Players { get; } = [];
 
     public LobbyViewModel(ISignalRService signalR, IGameStateService gameStateService, IAuthSessionService authSession, IApiService apiService)
@@ -42,7 +52,16 @@ public partial class LobbyViewModel : BaseViewModel,
         _apiService = apiService;
 
         IsConnected = _signalR.IsConnected;
-        //WeakReferenceMessenger.Default.RegisterAll(this);
+        IsActive = true;
+    }
+
+    /// <summary>
+    /// Reaktiviert das ViewModel nach einem Logout (Singleton-Lebensdauer).
+    /// Wird von LobbyPage.OnNavigatedTo aufgerufen.
+    /// </summary>
+    public void Activate()
+    {
+        IsConnected = _signalR.IsConnected;
         IsActive = true;
     }
 
@@ -96,6 +115,7 @@ public partial class LobbyViewModel : BaseViewModel,
     {
         await RunSafeAsync(async () =>
         {
+            IsActive = false;
             await _signalR.DisconnectAsync();
             await _apiService.LogoutAsync();
             await _gameStateService.ClearLocalGameDataAsync();
@@ -125,19 +145,39 @@ public partial class LobbyViewModel : BaseViewModel,
         });
     }
 
-    public async void Receive(GameStartedMessage message)
+    public void Receive(GameStartedMessage message)
     {
-        await MainThread.InvokeOnMainThreadAsync(() => Shell.Current.GoToAsync($"//{nameof(Views.GameBoardPage)}"));
+        MainThread.BeginInvokeOnMainThread(() =>
+        {
+            try
+            {
+                Shell.Current.GoToAsync(nameof(Views.GameBoardPage));
+            }
+            catch (Exception ex)
+            {
+                StatusMessage = $"Navigation fehlgeschlagen: {ex.Message}";
+            }
+        });
     }
 
     public void Receive(ErrorOccurredMessage message)
     {
-        StatusMessage = message.Value;
+        MainThread.BeginInvokeOnMainThread(() => StatusMessage = message.Value);
     }
 
     public void Receive(ConnectionStateChangedMessage message)
     {
-        IsConnected = message.Value;
+        MainThread.BeginInvokeOnMainThread(() => IsConnected = message.Value);
+    }
+
+    public void Receive(SyncStateChangedMessage message)
+    {
+        MainThread.BeginInvokeOnMainThread(() =>
+        {
+            IsSyncing = message.Value.IsSyncing;
+            SyncStatusText = message.Value.StatusText;
+            PendingSyncActions = message.Value.PendingActions;
+        });
     }
 
     private int GetCurrentPlayerId()

SlipItIn/ViewModels/LoginViewModel.cs

@@ -14,10 +14,10 @@ public partial class LoginViewModel : BaseViewModel
     private readonly IGameStateService _gameStateService;
 
     [ObservableProperty]
-    public partial string Email { get; set; }
+    private string email = string.Empty;
 
     [ObservableProperty]
-    public partial string Password { get; set; }
+    private string password = string.Empty;
 
     public LoginViewModel(IApiService apiService, IAuthSessionService authSession, ISignalRService signalR, IGameStateService gameStateService)
     {
@@ -28,7 +28,7 @@ public partial class LoginViewModel : BaseViewModel
     }
 
     [RelayCommand]
-    private Task GoToRegisterAsync() => Shell.Current.GoToAsync($"//{nameof(RegisterPage)}");
+    private Task GoToRegisterAsync() => Shell.Current.GoToAsync(nameof(RegisterPage));
 
     [RelayCommand]
     private async Task LoginAsync()
@@ -42,20 +42,40 @@ public partial class LoginViewModel : BaseViewModel
             });
 
             await _authSession.SetSessionAsync(response);
-            await _signalR.ConnectAsync(response.Token);
+
+            var connected = await _signalR.ConnectAsync(response.Token);
+            if (!connected)
+                throw new InvalidOperationException("Verbindung zum Spielserver fehlgeschlagen.");
+
             await _gameStateService.InitializeAsync();
-            await Shell.Current.GoToAsync($"//{nameof(LobbyPage)}");
+            await Shell.Current.GoToAsync(nameof(LobbyPage));
         }, "Anmeldung läuft...");
     }
 
     [RelayCommand]
     public async Task InitializeAsync()
     {
-        bool isAuthenticated = _authSession.IsAuthenticated;
+        if (!_authSession.IsAuthenticated)
+            return;
 
-        if ( isAuthenticated)
+        var sessionResult = await _apiService.ValidateSessionAsync();
+        if (sessionResult == SessionValidationResult.NetworkError)
+            return;
+
+        if (sessionResult == SessionValidationResult.Invalid)
         {
-            await Shell.Current.GoToAsync($"//{nameof(LobbyPage)}");
+            await _authSession.ClearSessionAsync();
+            await _gameStateService.ClearLocalGameDataAsync();
+            await _signalR.DisconnectAsync();
+            return;
         }
+
+        var token = _authSession.AccessToken;
+        if (string.IsNullOrWhiteSpace(token))
+            return;
+
+        var connected = await _signalR.ConnectAsync(token);
+        if (connected)
+            await Shell.Current.GoToAsync(nameof(LobbyPage));
     }
 }

SlipItIn/ViewModels/RegisterViewModel.cs

@@ -13,13 +13,13 @@ public partial class RegisterViewModel : BaseViewModel
     private readonly ISignalRService _signalR;
 
     [ObservableProperty]
-    public partial string Username { get; set; } = string.Empty;
+    private string username = string.Empty;
 
     [ObservableProperty]
-    public partial string Email { get; set; } = string.Empty;
+    private string email = string.Empty;
 
     [ObservableProperty]
-    public partial string Password { get; set; } = string.Empty;
+    private string password = string.Empty;
 
     public RegisterViewModel(IApiService apiService, IAuthSessionService authSession, ISignalRService signalR)
     {
@@ -44,8 +44,10 @@ public partial class RegisterViewModel : BaseViewModel
             });
 
             await _authSession.SetSessionAsync(response);
-            await _signalR.ConnectAsync(response.Token);
-            await Shell.Current.GoToAsync($"//{nameof(LobbyPage)}");
+            var connected = await _signalR.ConnectAsync(response.Token);
+            if (!connected)
+                throw new InvalidOperationException("Verbindung zum Spielserver fehlgeschlagen.");
+            await Shell.Current.GoToAsync(nameof(LobbyPage));
         }, "Registrierung läuft...");
     }
 }

SlipItIn/Views/ChallengeNotificationOverlay.xaml

@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="utf-8" ?>
 <ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
-             x:Class="SlipItIn.Views.ChallengeNotificationOverlay">
+             xmlns:vm="clr-namespace:SlipItIn.ViewModels"
+             x:Class="SlipItIn.Views.ChallengeNotificationOverlay"
+             x:DataType="vm:GameBoardViewModel">
     <Grid BackgroundColor="#88000000" IsVisible="{Binding IsChallengeVisible}" Padding="24">
-        <Frame VerticalOptions="Center" HorizontalOptions="Center">
+        <Border VerticalOptions="Center" HorizontalOptions="Center" Stroke="LightGray" StrokeShape="RoundRectangle 12" BackgroundColor="White" Padding="16">
             <VerticalStackLayout Spacing="10">
                 <Label Text="Du wurdest beschuldigt" FontAttributes="Bold" />
                 <Label Text="{Binding PendingChallenge.ChallengeId, StringFormat='ChallengeId: {0}'}" />
@@ -12,6 +14,6 @@
                     <Button Text="Ablehnen" Command="{Binding RejectChallengeCommand}" />
                 </HorizontalStackLayout>
             </VerticalStackLayout>
-        </Frame>
+        </Border>
     </Grid>
 </ContentView>

SlipItIn/Views/GameBoardPage.xaml

@@ -10,6 +10,9 @@
                 <Label Text="Spielbrett" FontSize="24" FontAttributes="Bold" />
                 <Label Text="{Binding CurrentRound, StringFormat='Runde: {0}'}" />
                 <Label Text="{Binding RoundTimeRemaining, StringFormat='Verbleibende Zeit: {0}s'}" />
+                <Label Text="{Binding IsConnected, StringFormat='Verbindung: {0}'}" TextColor="Gray" />
+                <Label Text="{Binding SyncStatusText}" TextColor="DodgerBlue" IsVisible="{Binding IsSyncing}" />
+                <Label Text="{Binding PendingSyncActions, StringFormat='Offline-Aktionen: {0}'}" TextColor="Gray" />
 
                 <Button Text="Status aktualisieren" Command="{Binding RefreshStateCommand}" />
 
@@ -17,7 +20,7 @@
                 <CollectionView ItemsSource="{Binding MyCards}">
                     <CollectionView.ItemTemplate>
                         <DataTemplate>
-                            <Frame Margin="0,4" Padding="10">
+                            <Border Margin="0,4" Padding="10" Stroke="LightGray" StrokeThickness="1" StrokeShape="RoundRectangle 10" BackgroundColor="White">
                                 <VerticalStackLayout>
                                     <Label Text="{Binding Text}" />
                                     <HorizontalStackLayout>
@@ -25,7 +28,7 @@
                                         <Button Text="Beschuldigen" Command="{Binding Source={RelativeSource AncestorType={x:Type ContentPage}}, Path=BindingContext.ChallengeCardCommand}" CommandParameter="{Binding .}" />
                                     </HorizontalStackLayout>
                                 </VerticalStackLayout>
-                            </Frame>
+                            </Border>
                         </DataTemplate>
                     </CollectionView.ItemTemplate>
                 </CollectionView>

SlipItIn/Views/GameBoardPage.xaml.cs

@@ -5,9 +5,23 @@ namespace SlipItIn.Views;
 
 public partial class GameBoardPage : ContentPage
 {
+    private readonly GameBoardViewModel _viewModel;
+
     public GameBoardPage()
     {
         InitializeComponent();
-        BindingContext = ServiceHelper.GetRequiredService<GameBoardViewModel>();
+        BindingContext = _viewModel = ServiceHelper.GetRequiredService<GameBoardViewModel>();
+    }
+
+    protected override void OnNavigatedTo(NavigatedToEventArgs args)
+    {
+        base.OnNavigatedTo(args);
+        _viewModel.StartRoundTimer();
+    }
+
+    protected override void OnNavigatedFrom(NavigatedFromEventArgs args)
+    {
+        base.OnNavigatedFrom(args);
+        _viewModel.StopRoundTimer();
     }
 }

SlipItIn/Views/LobbyPage.xaml

@@ -7,6 +7,8 @@
         <VerticalStackLayout Padding="24" Spacing="12">
             <Label Text="Lobby" FontSize="24" FontAttributes="Bold" />
             <Label Text="{Binding IsConnected, StringFormat='Verbindung: {0}'}" />
+            <Label Text="{Binding SyncStatusText}" TextColor="DodgerBlue" IsVisible="{Binding IsSyncing}" />
+            <Label Text="{Binding PendingSyncActions, StringFormat='Offline-Aktionen: {0}'}" TextColor="Gray" />
 
             <Button Text="Lobby erstellen" Command="{Binding CreateLobbyCommand}" />
 

SlipItIn/Views/LobbyPage.xaml.cs

@@ -5,9 +5,17 @@ namespace SlipItIn.Views;
 
 public partial class LobbyPage : ContentPage
 {
+    private readonly LobbyViewModel _viewModel;
+
     public LobbyPage()
     {
         InitializeComponent();
-        BindingContext = ServiceHelper.GetRequiredService<LobbyViewModel>();
+        BindingContext = _viewModel = ServiceHelper.GetRequiredService<LobbyViewModel>();
+    }
+
+    protected override void OnNavigatedTo(NavigatedToEventArgs args)
+    {
+        base.OnNavigatedTo(args);
+        _viewModel.Activate();
     }
 }

aspire.config.json

@@ -1,5 +1,5 @@
 {
   "appHost": {
-    "path": "SlipItIN.AppHost/SlipItIN.AppHost.csproj"
+    "path": "SlipItIn.AppHost/SlipItIn.AppHost.csproj"
   }
 }

openwiki/.last-update.json

@@ -1,6 +1,8 @@
 {
-  "updatedAt": "2026-07-26T11:33:42.070Z",
-  "command": "init",
-  "gitHead": "070727d5cd1fff7fdd7e0db903f1c696b0045ecd",
-  "model": "gemini-3.6-flash"
+  "updatedAt": "2026-08-08T18:09:49.042Z",
+  "command": "update",
+  "gitHead": "37616a93166c2ac0a46eedab276164f811043f4e",
+  "model": "gemini-3.6-flash",
+  "status": "complete",
+  "language": "en"
 }

openwiki/architecture/index.md

@@ -1,3 +1,3 @@
 # Files
 
-- [System Architecture & Security Overview](overview.md) - Technical architecture of SlipItIn, covering .NET Aspire orchestration, ASP.NET Core SignalR hub design, JWT authentication, and IDbContextFactory thread safety.
+- [System Architecture & Security Overview](overview.md) - Technical architecture of SlipItIn, covering .NET Aspire orchestration, ASP.NET Core SignalR hub, .NET MAUI MVVM client layer, WeakReferenceMessenger event routing, and dual-layer local storage.

openwiki/architecture/overview.md

@@ -1,13 +1,19 @@
 ---
 type: Architecture
 title: System Architecture & Security Overview
-description: Technical architecture of SlipItIn, covering .NET Aspire orchestration, ASP.NET Core SignalR hub design, JWT authentication, and IDbContextFactory thread safety.
-tags: [architecture, spire, signalr, jwt, efcore, security]
+description: Technical architecture of SlipItIn, covering .NET Aspire orchestration, ASP.NET Core SignalR hub, .NET MAUI MVVM client layer, WeakReferenceMessenger event routing, and dual-layer local storage.
+tags: [architecture, spire, signalr, jwt, efcore, security, maui, mvvm]
+openwiki:
+  roles: [architecture, domain]
+  change_kinds: [lifecycle, public-api]
+  source_paths: [SlipItIn/MauiProgram.cs, SlipItIn/Services/SignalRService.cs, SlipItIn/Services/GameStateService.cs, SlipItIn.Server/Program.cs, SlipItIn.Server/Hubs/GameHub.cs]
+  symbols: [SignalRService, GameStateService, LocalStorageService, GameHub, GameService, IDbContextFactory]
+  validation_commands: ["dotnet build SlipItIn.slnx"]
 ---
 
 # System Architecture & Security Overview
 
-**SlipItIn** is designed as a distributed, real-time application using modern .NET 10 architecture. This document details the orchestration model, backend service structure, security model, and concurrency safeguards.
+**SlipItIn** is designed as a distributed, real-time application using modern .NET 10 architecture. This document details the orchestration model, backend server structure, .NET MAUI MVVM client architecture, real-time connection resilience, messaging infrastructure, security model, and concurrency safeguards.
 
 The architectural foundation [orchestrates services with](/openwiki/operations/runbook.md) .NET Aspire, while [enforcing security & privacy on](/openwiki/domain/game-mechanics.md) domain entities and [serving real-time hub endpoints for](/openwiki/workflows/slip-and-challenge.md) all active game sessions. Source code structure for all architectural components can be found in the [Source Code Map](/openwiki/source-map.md).
 
@@ -32,14 +38,14 @@ The solution uses **.NET Aspire** to orchestrate application resources, services
 
 The backend is an ASP.NET Core Web API & SignalR application providing REST endpoints for user management and real-time WebSockets for game state synchronization.
 
-### Key Components
+### Key Backend Components
 
 1. **`Program.cs`**:
    - Registers `AddServiceDefaults()`, `AddNpgsqlDataSource("postgresdb")`, and `AddDbContextFactory<SlipItInDbContext>()`.
    - Configures JWT Bearer authentication with custom `OnMessageReceived` token resolution for SignalR.
    - Automatically executes database migrations (`db.Database.Migrate()`) at startup.
 2. **`AuthController.cs`**:
-   - Manages user registration (`/api/auth/register`) and authentication (`/api/auth/login`).
+   - Manages user registration (`/api/auth/register`), authentication (`/api/auth/login`), and profile retrieval (`/api/auth/me`).
    - Uses `BCrypt.Net` for secure password hashing.
    - Issues JWT tokens signed with `Jwt:Key`, containing `ClaimTypes.NameIdentifier`, `ClaimTypes.Name`, and `ClaimTypes.Email`.
 3. **`GameHub.cs`**:
@@ -48,6 +54,7 @@ The backend is an ASP.NET Core Web API & SignalR application providing REST endp
    - Extracts and verifies user claims, delegating state mutations to `IGameService`.
 4. **`GameService.cs`**:
    - Implements core business logic: game creation, player joins, card dealing, slip submission, challenge creation, and resolution.
+   - Adds `hostPlayer` directly to `game.Players` before `context.Games.Add(game)` to ensure EF Core navigation tracking consistency.
 
 ---
 
@@ -101,13 +108,103 @@ sequenceDiagram
     Client->>Hub: JoinLobby(lobbyCode)
     Hub->>Hub: GetAuthenticatedUserId()
     Hub->>Service: JoinGameAsync(lobbyCode, userId, connectionId)
-    Service->>DB: Create IDbContext Session & Save Player
-    Hub-->>Client: Broadcast "PlayerJoined" (GameStateDto)
+    Hub-->>Client: Broadcast PlayerJoined (GameStateDto)
 ```
+*Sequence diagram showing user authentication via REST and subsequent authenticated SignalR WebSocket connection.*
 
 ---
 
-## 4. Concurrency Safety: `IDbContextFactory`
+## 4. .NET MAUI Client Architecture (`SlipItIn`)
+
+The cross-platform client app uses the **MVVM Pattern** built on `CommunityToolkit.Mvvm` and Dependency Injection configured in `MauiProgram.cs`.
+
+```mermaid
+graph TD
+    subgraph UI_Layer["UI Layer (Views)"]
+        LoginPage["LoginPage"]
+        RegisterPage["RegisterPage"]
+        LobbyPage["LobbyPage"]
+        GameBoardPage["GameBoardPage"]
+    end
+
+    subgraph ViewModel_Layer["ViewModel Layer"]
+        LoginVM["LoginViewModel"]
+        RegisterVM["RegisterViewModel"]
+        LobbyVM["LobbyViewModel"]
+        GameBoardVM["GameBoardViewModel"]
+    end
+
+    subgraph Messaging_Layer["Messaging Layer"]
+        Messenger["WeakReferenceMessenger"]
+        Messages["Messages (GameStateChanged, PlayerHandChanged, ChallengeReceived)"]
+    end
+
+    subgraph Service_Layer["Service Layer"]
+        GameStateSvc["GameStateService"]
+        SignalRSvc["SignalRService"]
+        AuthSessionSvc["AuthSessionService"]
+        ApiSvc["ApiService"]
+        LocalStorageSvc["LocalStorageService"]
+    end
+
+    LoginPage --> LoginVM
+    RegisterPage --> RegisterVM
+    LobbyPage --> LobbyVM
+    GameBoardPage --> GameBoardVM
+
+    LobbyVM --> Messenger
+    GameBoardVM --> Messenger
+
+    GameStateSvc --> Messenger
+    GameStateSvc --> SignalRSvc
+    GameStateSvc --> LocalStorageSvc
+    LoginVM --> ApiSvc
+    LoginVM --> AuthSessionSvc
+    LoginVM --> SignalRSvc
+```
+*Layered architecture diagram of the .NET MAUI client showing Views, ViewModels, WeakReferenceMessenger, and Service implementations.*
+
+### Dependency Injection & Service Registration (`MauiProgram.cs`)
+- **Singletons**: `IAppConfigurationService` (`AppConfigurationService`), `ILocalStorageService` (`LocalStorageService`), `IAuthSessionService` (`AuthSessionService`), `IApiService` (`ApiService`), `ISignalRService` (`SignalRService`), `IGameStateService` (`GameStateService`), `LobbyViewModel`, `GameBoardViewModel`.
+- **Transients**: `LoginViewModel`, `RegisterViewModel`.
+- **Service Locator Helper**: `ServiceHelper.Services` captures `app.Services` at startup to allow static access where constructor DI is unavailable.
+
+### Decoupled Messaging Infrastructure (`WeakReferenceMessenger`)
+To avoid memory leaks caused by long-lived event subscriptions in ViewModels, `GameStateService` translates raw `ISignalRService` hub events into strongly-typed messages dispatched via `WeakReferenceMessenger.Default`:
+
+- `LobbyCreatedMessage`: Dispatched when a new game lobby code is issued by the server.
+- `GameStateChangedMessage`: Dispatched when public game state or player list updates.
+- `GameStartedMessage`: Dispatched when the game transitions to `InProgress`.
+- `PlayerHandChangedMessage`: Dispatched when a player receives or updates private phrase cards.
+- `ChallengeReceivedMessage`: Dispatched when a player is directly targeted by a slip challenge.
+- `ErrorOccurredMessage`: Dispatched when a hub or network error occurs.
+- `ConnectionStateChangedMessage`: Dispatched when SignalR connection drops or reconnects.
+
+ViewModels implement `IRecipient<TMessage>` and register via `WeakReferenceMessenger.Default.RegisterAll(this)` to receive automated UI updates.
+
+### Real-Time Connection Resilience & Auto-Reconnect
+`SignalRService` configures exponential backoff for WebSocket reconnection:
+
+```csharp
+_hubConnection = new HubConnectionBuilder()
+    .WithUrl(_configuration.HubUrl, options =>
+    {
+        options.AccessTokenProvider = () => Task.FromResult<string?>(token);
+    })
+    .WithAutomaticReconnect([TimeSpan.Zero, TimeSpan.FromSeconds(2), TimeSpan.FromSeconds(10), TimeSpan.FromSeconds(30)])
+    .Build();
+```
+
+When connection drops, `SignalRService` emits `ConnectionStateChanged`. Upon reconnection, `GameStateService` automatically triggers `ResyncAsync()` to fetch current state via `RequestGameStateAsync()` and flush locally queued offline actions.
+
+### Dual-Layer Storage Security Model (`LocalStorageService`)
+To satisfy security and privacy constraints:
+1. **`SecureStorage` (Platform Encrypted Storage)**: Used strictly for `AuthTokenKey` (`auth_token`). Prevents plaintext access to active JWT credentials.
+2. **`Preferences` (Application Key-Value Settings)**: Used for non-sensitive cached data (`auth_user`, `game_state`, `player_hand`, and `queued_actions`).
+
+---
+
+## 5. Concurrency Safety: `IDbContextFactory`
 
 SignalR hubs process concurrent requests from multiple clients over persistent connections. Using a standard Scoped `DbContext` in SignalR leads to thread conflict exceptions (`InvalidOperationException: A second operation was started on this context instance before a previous operation completed`).
 
@@ -119,7 +216,7 @@ SlipItIn solves this by registering EF Core with `AddDbContextFactory<SlipItInDb
 
 ---
 
-## 5. Data Privacy Isolation Model
+## 6. Data Privacy Isolation Model
 
 To prevent players from inspecting opponent cards via network trace analysis, SlipItIn strictly separates public and private data DTOs:
 
@@ -127,3 +224,30 @@ To prevent players from inspecting opponent cards via network trace analysis, Sl
 * **`PlayerHandDto` (Private)**: Direct unicast message sent *only* to the specific player's SignalR `ConnectionId`. Contains card text (`CardId`, `PhraseId`, `Text`, `IsUsed`).
 
 This architecture guarantees that players cannot see opponent phrase cards, even if they inspect raw WebSocket packets.
+
+---
+
+## 7. Guidance for Future Agents & Developers
+
+When extending or modifying the system architecture:
+
+- **When to Consult**: Consult this document before adding new real-time SignalR methods, introducing client ViewModels, modifying storage mechanisms, or altering server authentication logic.
+- **Runtime Invariants**:
+  - `GameHub` methods must validate caller claims via `GetAuthenticatedUserId()` and `ValidatePlayerAccessAsync()`.
+  - Client ViewModels must consume `WeakReferenceMessenger` messages rather than subscribing directly to `ISignalRService` C# events.
+  - JWT tokens must never be persisted in `Preferences`; always use `SecureStorage`.
+- **Extension Points**:
+  - New real-time server messages: Add method to `GameHub`, add event to `ISignalRService`, add message class in `SlipItIn/Messages/`, update `GameStateService` listener.
+  - New ViewModels: Register as Transient (dialogs/auth) or Singleton (main navigation screens) in `MauiProgram.cs`.
+- **Primary Source Files**:
+  - `SlipItIn/MauiProgram.cs`
+  - `SlipItIn/Services/SignalRService.cs`
+  - `SlipItIn/Services/GameStateService.cs`
+  - `SlipItIn/Services/LocalStorageService.cs`
+  - `SlipItIn.Server/Hubs/GameHub.cs`
+  - `SlipItIn.Server/Services/GameService.cs`
+- **Focused Checks**: Build and verify project references across client, server, and shared libraries.
+- **Minimal Validation Command**:
+  ```bash
+  dotnet build SlipItIn.slnx
+  ```

openwiki/domain/game-mechanics.md

@@ -1,21 +1,27 @@
 ---
 type: Domain Model
 title: Game Domain & State Models
-description: Detailed domain model and state lifecycles for SlipItIn games, rounds, phrase decks, players, and challenges.
-tags: [domain, models, state-machine, entity-framework, privacy]
+description: Detailed domain model and state lifecycles for SlipItIn games, rounds, phrase decks, players, challenges, and client offline action queue.
+tags: [domain, models, state-machine, entity-framework, privacy, offline-queue]
+openwiki:
+  roles: [domain]
+  change_kinds: [public-api, lifecycle]
+  source_paths: [SlipItIn.Shared/Models/Game.cs, SlipItIn.Shared/Models/Player.cs, SlipItIn/Models/QueuedGameAction.cs, SlipItIn.Shared/DTOs/GameStateDto.cs]
+  symbols: [Game, Player, PlayerCard, SlipChallenge, QueuedGameAction, GameStateDto, PlayerHandDto]
+  validation_commands: ["dotnet build SlipItIn.Shared/SlipItIn.Shared.csproj"]
 ---
 
 # Game Domain & State Models
 
-This page describes the core domain entities, relational schema, state machines, and data transfer objects (DTOs) that form the foundation of the SlipItIn game engine.
+This page describes the core domain entities, relational schema, state machines, offline action queue models, and data transfer objects (DTOs) that form the foundation of the SlipItIn game engine.
 
-The domain model [is secured by data privacy models defined in](/openwiki/architecture/overview.md) the system architecture, [defines state lifecycles executed by](/openwiki/workflows/slip-and-challenge.md) real-time game workflows, and [maps domain classes in C# project files indexed in](/openwiki/source-map.md) the source map (`SlipItIn.Shared/Models/` and `SlipItIn.Shared/DTOs/`).
+The domain model [is secured by data privacy models defined in](/openwiki/architecture/overview.md) the system architecture, [defines state lifecycles executed by](/openwiki/workflows/slip-and-challenge.md) real-time game workflows, and [maps domain classes in C# project files indexed in](/openwiki/source-map.md) the source map (`SlipItIn.Shared/Models/`, `SlipItIn.Shared/DTOs/`, and `SlipItIn/Models/`).
 
 ---
 
 ## 1. Entity Relationship Diagram (ERD)
 
-The database schema is managed via Entity Framework Core (`SlipItInDbContext`) targeting PostgreSQL.
+The backend database schema is managed via Entity Framework Core (`SlipItInDbContext`) targeting PostgreSQL.
 
 ```mermaid
 erDiagram
@@ -70,19 +76,20 @@ erDiagram
         ChallengeStatus Status
     }
 
-    User ||--o{ Game : "hosts"
-    User ||--o{ Player : "participates as"
-    User ||--o{ Phrase : "creates"
-    Game ||--o{ Player : "contains"
-    Game ||--o{ GameRound : "has"
-    Player ||--o{ PlayerCard : "holds"
-    Phrase ||--o{ PlayerCard : "used in"
-    GameRound ||--o{ PlayerCard : "active in"
-    GameRound ||--o{ SlipChallenge : "contains"
-    Player ||--o{ SlipChallenge : "challenges"
-    Player ||--o{ SlipChallenge : "target of"
-    PlayerCard ||--o{ SlipChallenge : "targeted by"
+    User ||--o{ Game : hosts
+    User ||--o{ Player : participates_as
+    User ||--o{ Phrase : creates
+    Game ||--o{ Player : contains
+    Game ||--o{ GameRound : has
+    Player ||--o{ PlayerCard : holds
+    Phrase ||--o{ PlayerCard : used_in
+    GameRound ||--o{ PlayerCard : active_in
+    GameRound ||--o{ SlipChallenge : contains
+    Player ||--o{ SlipChallenge : challenges
+    Player ||--o{ SlipChallenge : target_of
+    PlayerCard ||--o{ SlipChallenge : targeted_by
 ```
+*Entity Relationship Diagram showing relational database schema for users, games, players, phrases, cards, rounds, and challenges.*
 
 ---
 
@@ -125,7 +132,19 @@ Represents an accusation made by one player against another player's submitted s
 
 ---
 
-## 3. Enumerations & State Lifecycles
+## 3. Client State & Offline Action Queue Models (`SlipItIn/Models`)
+
+### `QueuedGameAction`
+Represents a game action (such as `SubmitSlip` or `ChallengeSlip`) initiated on the client while offline (`!SignalRService.IsConnected`).
+* **Properties**:
+  * `Method`: Target SignalR hub method name (e.g. `"SubmitSlip"`, `"ChallengeSlip"`).
+  * `ArgumentsJson`: JSON serialized array of method arguments.
+  * `CreatedAtUtc`: Timestamp recording when the action was taken.
+* **Lifecycle**: Enqueued into `Preferences` via `GameStateService.EnqueueActionAsync()`, replayed sequentially upon reconnection via `GameStateService.FlushQueuedActionsAsync()`, and removed from storage.
+
+---
+
+## 4. Enumerations & State Lifecycles
 
 ### Game Status (`GameStatus`)
 ```mermaid
@@ -136,6 +155,7 @@ stateDiagram-v2
     Lobby --> Cancelled: Host cancels
     InProgress --> Cancelled: Session abort
 ```
+*State diagram illustrating lifecycle transitions of a game session from lobby creation to completion or cancellation.*
 
 * **`Lobby`**: Waiting for players to join and set ready status.
 * **`InProgress`**: Active gameplay with dealt cards and active rounds.
@@ -151,6 +171,7 @@ stateDiagram-v2
     Resolving --> Active: Challenge resolved
     Active --> Completed: Timer expires / All phrases used
 ```
+*State diagram illustrating round lifecycles from card dealing to challenge resolution.*
 
 ### Challenge Status (`ChallengeStatus`)
 * **`Pending`**: Accusation registered, awaiting response from the accused player.
@@ -159,13 +180,33 @@ stateDiagram-v2
 
 ---
 
-## 4. Data Transfer Objects (DTOs) & Data Privacy
+## 5. Data Transfer Objects (DTOs) & Data Privacy
 
 To enforce security and data privacy ([Architecture Overview](/openwiki/architecture/overview.md)), the backend exposes decoupled DTOs in `SlipItIn.Shared/DTOs`:
 
 | DTO | Visibility | Purpose & Content |
 |---|---|---|
+| `LoginRequestDto` | Direct REST | Credentials for authentication: `Email`, `Password`. |
+| `RegisterRequestDto` | Direct REST | Account creation details: `Username`, `Email`, `Password`. |
 | `AuthResponseDto` | Direct REST | JWT Access Token, Expiration, Username, Email. |
 | `GameStateDto` | Broadcast (Group) | Public lobby/game status: `GameId`, `LobbyCode`, `Status`, `CurrentRound`, `RoundTimeRemaining`, `Players` (`PlayerInfoDto` array containing `PlayerId`, `Username`, `Score`, `IsReady`, and `CardCount`). **No card text.** |
 | `PlayerHandDto` | Unicast (Client) | Private hand data sent strictly to the card owner: `PlayerId`, `Cards` (`PlayerCardDto` array containing `CardId`, `PhraseId`, `Text`, `IsUsed`). |
 | `SlipChallengeDto` | Unicast / Group | Challenge notification: `ChallengeId`, `ChallengingPlayerId`, `TargetPlayerId`, `TargetCardId`, `Status`, `CreatedAt`. |
+
+---
+
+## 6. Guidance for Future Agents & Developers
+
+- **When to Consult**: Consult this page when adding domain attributes, extending DTOs, adding new game state statuses, or modifying offline action serialization.
+- **Invariants**:
+  - `PlayerCard.IsUsed` transitions from `false` to `true` upon `SubmitSlip` and cannot be reverted without server intervention.
+  - `QueuedGameAction.ArgumentsJson` must store arguments in the exact order and type expected by `GameHub` methods.
+- **Primary Source Files**:
+  - `SlipItIn.Shared/Models/Game.cs`
+  - `SlipItIn.Shared/Models/PlayerCard.cs`
+  - `SlipItIn.Shared/DTOs/GameStateDto.cs`
+  - `SlipItIn/Models/QueuedGameAction.cs`
+- **Minimal Validation Command**:
+  ```bash
+  dotnet build SlipItIn.Shared/SlipItIn.Shared.csproj
+  ```

openwiki/domain/index.md

@@ -1,3 +1,3 @@
 # Files
 
-- [Game Domain & State Models](game-mechanics.md) - Detailed domain model and state lifecycles for SlipItIn games, rounds, phrase decks, players, and challenges.
+- [Game Domain & State Models](game-mechanics.md) - Detailed domain model and state lifecycles for SlipItIn games, rounds, phrase decks, players, challenges, and client offline action queue.

openwiki/index.md

@@ -4,8 +4,8 @@ okf_version: "0.1"
 
 # Files
 
-- [SlipItIn Code Wiki Quickstart](quickstart.md) - Entrypoint for SlipItIn - a real-time multiplayer party game built with .NET 10, MAUI, ASP.NET Core SignalR, EF Core PostgreSQL, and .NET Aspire.
-- [Source Code Map & Navigation Directory](source-map.md) - Practical navigation guide mapping source files across projects to system domains and responsibilities.
+- [SlipItIn Code Wiki Quickstart](quickstart.md) - Entrypoint for SlipItIn - a real-time multiplayer party game built with .NET 10, MAUI MVVM, ASP.NET Core SignalR, EF Core PostgreSQL, and .NET Aspire.
+- [Source Code Map & Navigation Directory](source-map.md) - Practical navigation guide mapping source files across projects to system domains, viewmodels, services, and responsibilities.
 
 # Directories
 

openwiki/operations/index.md

@@ -1,3 +1,3 @@
 # Files
 
-- [Operations, Environment Setup & Testing Guidance](runbook.md) - Operational guide for launching SlipItIn with .NET Aspire, running EF Core PostgreSQL migrations, configuring JWT secrets, and executing tests.
+- [Operations, Environment Setup & Testing Guidance](runbook.md) - Operational guide for launching SlipItIn with .NET Aspire, running EF Core PostgreSQL migrations, configuring secrets, and executing client/server verification tests.

openwiki/operations/runbook.md

@@ -1,15 +1,21 @@
 ---
 type: Runbook
 title: Operations, Environment Setup & Testing Guidance
-description: Operational guide for launching SlipItIn with .NET Aspire, running EF Core PostgreSQL migrations, configuring JWT secrets, and executing tests.
-tags: [operations, runbook, spire, postgresql, migrations, testing]
+description: Operational guide for launching SlipItIn with .NET Aspire, running EF Core PostgreSQL migrations, configuring secrets, and executing client/server verification tests.
+tags: [operations, runbook, spire, postgresql, migrations, testing, mvvm, offline-queue]
+openwiki:
+  roles: [operations, testing]
+  change_kinds: [lifecycle, public-api]
+  source_paths: [SlipItIn.AppHost/AppHost.cs, SlipItIn.Server/Program.cs, SlipItIn/MauiProgram.cs]
+  symbols: [AppHost, Program, MauiProgram]
+  validation_commands: ["dotnet build SlipItIn.slnx"]
 ---
 
 # Operations, Environment Setup & Testing Guidance
 
-This runbook provides actionable instructions for local development setup, starting services via .NET Aspire, executing Entity Framework Core migrations, configuring environment keys, and running tests.
+This runbook provides actionable instructions for local development setup, starting services via .NET Aspire, executing Entity Framework Core migrations, configuring environment keys, running client/server applications, and executing targeted test scenarios.
 
-This guide [configures environment parameters for](/openwiki/architecture/overview.md) the backend architecture, [manages database migrations for entities in](/openwiki/domain/game-mechanics.md) the domain model, [verifies real-time event flows defined in](/openwiki/workflows/slip-and-challenge.md) the workflow guide, and [references source entrypoints cataloged in](/openwiki/source-map.md) the source map.
+This guide [configures environment parameters for](/openwiki/architecture/overview.md) the backend and client architecture, [manages database migrations for entities in](/openwiki/domain/game-mechanics.md) the domain model, [verifies real-time event flows defined in](/openwiki/workflows/slip-and-challenge.md) the workflow guide, and [references source entrypoints cataloged in](/openwiki/source-map.md) the source map.
 
 ---
 
@@ -81,7 +87,7 @@ dotnet ef database update --project SlipItIn.Server --startup-project SlipItIn.S
 
 ## 4. Testing Guidance & Verification Scenarios
 
-When developing or extending SlipItIn features, verify the core architecture through targeted test scenarios specified in `Agents/Architecture.md`:
+When developing or extending SlipItIn features, verify the core architecture through these targeted test scenarios:
 
 ### 1. JWT Authentication & Claims Tests
 * **Test Objective**: Verify `GameHub` rejects unauthenticated WebSocket connections or missing token query parameters.
@@ -91,14 +97,34 @@ When developing or extending SlipItIn features, verify the core architecture thr
 * **Test Objective**: Verify Player A cannot manipulate Player B's cards or state.
 * **Verification**: Authenticate as User A and attempt to call `GameHub.SubmitSlip(gameId, playerBId, cardId)`. Verify that `ValidatePlayerAccessAsync` throws `UnauthorizedAccessException` and returns an error response.
 
-### 3. Concurrency & Race Condition Tests
+### 3. Client MVVM Decoupled Messaging Tests
+* **Test Objective**: Confirm `GameStateService` translates SignalR events into `WeakReferenceMessenger` messages without memory leak risk.
+* **Verification**: Trigger a `GameStateUpdated` event on `SignalRService`. Confirm that `LobbyViewModel` and `GameBoardViewModel` receive `GameStateChangedMessage` and update their observable collections cleanly.
+
+### 4. Offline Action Queueing & Resync Verification
+* **Test Objective**: Verify actions taken while disconnected are stored locally and replayed upon reconnection.
+* **Verification**:
+  1. Disconnect network or stop `SignalRService`.
+  2. Invoke `GameBoardViewModel.SubmitSlipAsync(card)`. Confirm `QueuedGameAction` is written to `Preferences`.
+  3. Re-establish connection. Confirm `GameStateService.ResyncAsync()` calls `RequestGameStateAsync()` and replays the queued action via `SendQueuedActionAsync()`.
+
+### 5. Dual-Layer Local Storage Verification
+* **Test Objective**: Confirm sensitive tokens are isolated in `SecureStorage` while non-sensitive state stays in `Preferences`.
+* **Verification**: Inspect local device storage after login. Verify `auth_token` is stored via platform `SecureStorage` and `game_state` / `queued_actions` are saved in `Preferences`.
+
+### 6. Concurrency & Race Condition Tests
 * **Test Objective**: Confirm `IDbContextFactory` handles simultaneous WebSocket calls without thread collision.
 * **Verification**: Simulate 5 parallel calls to `GameHub.ChallengeSlip()` or `SubmitSlip()` across multiple clients. Verify that all calls complete cleanly without `InvalidOperationException` from DbContext.
 
-### 4. Data Privacy Isolation Verification
-* **Test Objective**: Confirm card text is never broadcast in public group messages.
-* **Verification**: Capture SignalR `PlayerJoined` and `GameStateUpdated` payloads. Inspect JSON content to confirm only `CardCount` is present and no phrase card `Text` is leaked.
+---
 
-### 5. False Accusation Penalty Verification
-* **Test Objective**: Verify penalty card transfer when a challenge is rejected.
-* **Verification**: Submit a challenge against a valid slip, then call `ResolveChallenge(challengeId, approved: false)`. Verify in the database that `PlayerCard.PlayerId` is reassigned to the challenger's `PlayerId`.
+## 5. Guidance for Future Agents & Developers
+
+- **When to Consult**: Refer to this runbook for local environment setup, Aspire startup commands, EF Core migration commands, and test verification procedures.
+- **Invariants**:
+  - Always run migrations using `SlipItIn.Server` as both project and startup-project.
+  - Test offline queue flushing before submitting client-side real-time changes.
+- **Minimal Validation Command**:
+  ```bash
+  dotnet build SlipItIn.slnx
+  ```

openwiki/quickstart.md

@@ -1,15 +1,21 @@
 ---
 type: Overview
 title: SlipItIn Code Wiki Quickstart
-description: Entrypoint for SlipItIn - a real-time multiplayer party game built with .NET 10, MAUI, ASP.NET Core SignalR, EF Core PostgreSQL, and .NET Aspire.
-tags: [quickstart, overview, slipitin, dotnet10, spire]
+description: Entrypoint for SlipItIn - a real-time multiplayer party game built with .NET 10, MAUI MVVM, ASP.NET Core SignalR, EF Core PostgreSQL, and .NET Aspire.
+tags: [quickstart, overview, slipitin, dotnet10, spire, maui, mvvm]
+openwiki:
+  roles: [architecture, domain, workflow]
+  change_kinds: [public-api, lifecycle]
+  source_paths: [SlipItIn/MauiProgram.cs, SlipItIn.Server/Program.cs, SlipItIn.AppHost/AppHost.cs]
+  symbols: [MauiProgram, SignalRService, GameStateService, GameHub, GameService]
+  validation_commands: ["dotnet build SlipItIn.slnx"]
 ---
 
 # SlipItIn Code Wiki Quickstart
 
 Welcome to the **SlipItIn** repository wiki. SlipItIn is a real-time multiplayer party game where players receive secret phrase cards and attempt to "slip" those phrases into everyday conversations or text chats without getting caught by other players.
 
-The solution is built using **.NET 10**, leveraging **ASP.NET Core Web API & SignalR** for the backend engine, **Entity Framework Core (Npgsql / PostgreSQL)** for data persistence, **.NET MAUI** for the cross-platform client app, and **.NET Aspire** for distributed cloud-native orchestration and telemetry.
+The solution is built using **.NET 10**, leveraging **ASP.NET Core Web API & SignalR** for the backend engine, **Entity Framework Core (Npgsql / PostgreSQL)** for data persistence, **.NET MAUI (MVVM Pattern)** for the cross-platform client app, and **.NET Aspire** for distributed cloud-native orchestration and telemetry.
 
 ---
 
@@ -21,47 +27,62 @@ The repository is organized as a multi-project .NET solution (`SlipItIn.slnx`):
 SlipItIN/
 ├── SlipItIn.AppHost/          # .NET Aspire AppHost orchestrator (pgsql + server + client)
 ├── SlipItIn.Server/           # ASP.NET Core Web API + SignalR Hub + Game Engine
-├── SlipItIn.Shared/           # Shared Class Library (Models & DTOs)
+├── SlipItIn.Shared/           # Shared Class Library (Models, DTOs & Enums)
 ├── SlipItIn.ServiceDefaults/  # Aspire OpenTelemetry, Health Checks & Service Discovery
-└── SlipItIn/                  # .NET MAUI Client App (Android, iOS, MacCatalyst, Windows)
+└── SlipItIn/                  # .NET MAUI Client App (MVVM: Views, ViewModels, Services, Messages)
 ```
 
-The system architecture [orchestrates services with](/openwiki/operations/runbook.md) .NET Aspire and [enforces security and privacy on](/openwiki/domain/game-mechanics.md) all domain entities. For a deep dive into the backend design, JWT security, and concurrency safety, see the [System Architecture & Security Overview](/openwiki/architecture/overview.md).
+The system architecture [orchestrates services with](/openwiki/operations/runbook.md) .NET Aspire and [enforces security and privacy on](/openwiki/domain/game-mechanics.md) all domain entities. For a deep dive into backend security, SignalR real-time client integration, MVVM architecture, and offline queueing, see the [System Architecture & Security Overview](/openwiki/architecture/overview.md).
 
 ```mermaid
 graph TD
-    MAUI[SlipItIn .NET MAUI Client] -->|REST / API| Server[SlipItIn.Server ASP.NET Core]
-    MAUI -->|SignalR WebSockets| Hub[GameHub /hubs/game]
-    Server -->|IDbContextFactory| DB[(PostgreSQL Database)]
-    AppHost[.NET Aspire AppHost] -->|Orchestrates| Server
+    subgraph MAUI_Client["SlipItIn .NET MAUI Client"]
+        Views["Views (LoginPage, LobbyPage, GameBoardPage)"] --> ViewModels["ViewModels (LoginVM, LobbyVM, GameBoardVM)"]
+        ViewModels --> GameState["GameStateService"]
+        GameState --> SignalR["SignalRService"]
+        GameState --> LocalStorage["LocalStorageService (SecureStorage & Preferences)"]
+        ViewModels --> ApiService["ApiService (REST Auth)"]
+    end
+    
+    ApiService -->|REST /api/auth| AuthCtrl["AuthController"]
+    SignalR -->|WebSockets /hubs/game| Hub["GameHub"]
+    Hub --> Service["GameService"]
+    AuthCtrl --> DB[("PostgreSQL Database")]
+    Service -->|IDbContextFactory| DB
+    AppHost[".NET Aspire AppHost"] -->|Orchestrates| Server["SlipItIn.Server"]
     AppHost -->|Provisions| DB
-    Server -->|Uses Defaults| ServiceDefaults[SlipItIn.ServiceDefaults]
 ```
+*System architecture diagram illustrating .NET MAUI MVVM client layer, backend REST/SignalR APIs, and .NET Aspire PostgreSQL orchestration.*
 
 ---
 
 ## 2. Core Game Loop & Mechanics
 
-1. **Lobby Creation**: Host creates a game lobby with a 6-character code. Players join via code.
-2. **Card Dealing**: Upon game start, each player receives a private hand of 5 secret phrase cards (`PlayerHandDto`).
-3. **Phrase Slipping**: During normal conversation, a player speaks or types one of their phrases and clicks **Submit Slip**.
-4. **Slip Challenge**: Opponents suspecting a fake phrase can issue a **Slip Challenge**.
-   - **Justified Accusation (Approved)**: Target phrase was an invalid slip.
-   - **False Accusation (Rejected)**: Target phrase was legitimate. The accuser receives the card as a penalty (expanding their hand size beyond 5).
+1. **Authentication & Session**: Player registers or logs in via `LoginPage` / `RegisterPage`. `AuthSessionService` stores the JWT token in `SecureStorage`.
+2. **Lobby Creation**: Host creates a lobby on `LobbyPage`, generating a 6-character code. Players join using the code.
+3. **Card Dealing**: Upon game start, each player receives a private hand of 5 secret phrase cards (`PlayerHandDto`) via SignalR unicast.
+4. **Phrase Slipping**: During normal conversation, a player speaks or types one of their phrases and clicks **Submit Slip** on `GameBoardPage`. If offline, actions queue locally in `QueuedGameAction` and flush automatically upon reconnection.
+5. **Slip Challenge**: Opponents suspecting a fake phrase can issue a **Slip Challenge**.
+   - **Justified Accusation (Approved)**: Target phrase was an invalid slip. Card remains with accused player.
+   - **False Accusation (Rejected)**: Target phrase was legitimate. The accuser receives the phrase card as a penalty.
 
 To learn how game events flow across SignalR in real time, inspect the [Slip & Challenge Workflows](/openwiki/workflows/slip-and-challenge.md).
 
 ---
 
-## 3. Wiki Navigation Map
+## 3. Task Routing & Navigation Map
 
-Explore specific documentation sections for technical details:
+The following task routing table directs future engineers and automated agents to relevant wiki documentation, source entry points, key symbols, and verification commands for common modification scenarios:
 
-- **[System Architecture & Security Overview](/openwiki/architecture/overview.md)**: Explains .NET Aspire orchestration, JWT bearer authentication, claims validation, `IDbContextFactory` thread safety, and public vs. private data isolation.
-- **[Game Domain & State Models](/openwiki/domain/game-mechanics.md)**: Details domain entities (`User`, `Game`, `Player`, `Phrase`, `PlayerCard`, `GameRound`, `SlipChallenge`) and their state lifecycles.
-- **[Slip & Challenge Workflows](/openwiki/workflows/slip-and-challenge.md)**: Details step-by-step game loop execution, real-time SignalR notifications, and penalty rules.
-- **[Source Code Map](/openwiki/source-map.md)**: Directory and file navigation index mapping repository paths to technical domains.
-- **[Operations & Runbook](/openwiki/operations/runbook.md)**: Instructions for running the app with Aspire, executing PostgreSQL EF Core migrations, configuration keys, and testing strategies.
+| Intent / Change Area | Relevant Wiki Page | Source Entry Points | Key Symbols / Types | Focused Checks | Minimal Validation Command |
+|---|---|---|---|---|---|
+| **MAUI Client ViewModels & Pages** | [Architecture Overview](/openwiki/architecture/overview.md) | `SlipItIn/ViewModels/`, `SlipItIn/Views/` | `LobbyViewModel`, `GameBoardViewModel`, `LoginViewModel` | Inspect MVVM command handlers and `WeakReferenceMessenger` bindings | `dotnet build SlipItIn/SlipItIn.csproj` |
+| **Client SignalR & Messaging** | [Slip & Challenge Workflows](/openwiki/workflows/slip-and-challenge.md) | `SlipItIn/Services/SignalRService.cs`, `SlipItIn/Services/GameStateService.cs` | `ISignalRService`, `IGameStateService`, `WeakReferenceMessenger` | Verify auto-reconnect backoff and message dispatching | `dotnet build SlipItIn/SlipItIn.csproj` |
+| **Offline Action Queue & Resync** | [Slip & Challenge Workflows](/openwiki/workflows/slip-and-challenge.md) | `SlipItIn/Services/GameStateService.cs`, `SlipItIn/Models/QueuedGameAction.cs` | `QueuedGameAction`, `EnqueueActionAsync`, `FlushQueuedActionsAsync` | Verify offline queueing in `Preferences` and flush on reconnect | `dotnet build SlipItIn/SlipItIn.csproj` |
+| **Local Storage & Auth Session** | [Architecture Overview](/openwiki/architecture/overview.md) | `SlipItIn/Services/LocalStorageService.cs`, `SlipItIn/Services/AuthSessionService.cs` | `ILocalStorageService`, `IAuthSessionService`, `SecureStorage` | Confirm JWT stored in `SecureStorage` and state in `Preferences` | `dotnet build SlipItIn/SlipItIn.csproj` |
+| **Backend Game Engine & Hub** | [Architecture Overview](/openwiki/architecture/overview.md) | `SlipItIn.Server/Hubs/GameHub.cs`, `SlipItIn.Server/Services/GameService.cs` | `GameHub`, `GameService`, `IDbContextFactory` | Test JWT claim extraction and EF Core DbContext session isolation | `dotnet build SlipItIn.Server/SlipItIn.Server.csproj` |
+| **Domain Models & DTOs** | [Game Domain & State Models](/openwiki/domain/game-mechanics.md) | `SlipItIn.Shared/Models/`, `SlipItIn.Shared/DTOs/` | `GameStateDto`, `PlayerHandDto`, `SlipChallengeDto`, `QueuedGameAction` | Confirm card privacy isolation between public state and private hand | `dotnet build SlipItIn.Shared/SlipItIn.Shared.csproj` |
+| **Aspire & Infrastructure Setup** | [Operations & Runbook](/openwiki/operations/runbook.md) | `SlipItIn.AppHost/AppHost.cs`, `SlipItIn.ServiceDefaults/` | `AppHost`, `AddServiceDefaults`, `AddPostgres` | Validate Aspire service references and PostgreSQL container creation | `dotnet run --project SlipItIn.AppHost/SlipItIn.AppHost.csproj` |
 
 ---
 
@@ -72,6 +93,8 @@ When modifying this repository, strictly adhere to these core rules:
 1. **IDbContextFactory Thread Safety**: Never inject a scoped `SlipItInDbContext` into SignalR hubs or singleton services. Always use `IDbContextFactory<SlipItInDbContext>.CreateDbContext()` to prevent DbContext concurrency exceptions during concurrent WebSocket calls ([Architecture Overview](/openwiki/architecture/overview.md)).
 2. **Data Privacy Isolation**: Do not leak card text into public DTOs. Public game state must be broadcast using `GameStateDto` (card counts only), while private cards are dispatched strictly via `PlayerHandDto` to individual client connections ([Domain Mechanics](/openwiki/domain/game-mechanics.md)).
 3. **Server-Side Validation**: SignalR client calls represent intent ("I want to challenge X"). The server MUST re-verify JWT claims, player game membership, card ownership, and round status inside `GameHub.cs` and `GameService.cs` before mutating state ([Slip & Challenge Workflows](/openwiki/workflows/slip-and-challenge.md)).
+4. **Decoupled Client Messaging**: MAUI ViewModels MUST NOT consume `ISignalRService` events directly for UI updates. Always route events through `IGameStateService` via `WeakReferenceMessenger` messages (`GameStateChangedMessage`, `PlayerHandChangedMessage`, `ChallengeReceivedMessage`) to prevent memory leaks and dangling subscriptions ([Architecture Overview](/openwiki/architecture/overview.md)).
+5. **Dual-Layer Local Storage**: Always store sensitive credentials (JWT access tokens) in platform `SecureStorage`. Non-sensitive UI states, cached game data, and offline action queues MUST be persisted in `Preferences` ([Architecture Overview](/openwiki/architecture/overview.md)).
 
 ---
 
@@ -79,6 +102,4 @@ When modifying this repository, strictly adhere to these core rules:
 
 The following features and components are specified in specification documents (`Agents/ProjectPlan.md` and `Agents/Architecture.md`) and backlogged for upcoming development iterations:
 
-- **MAUI Client Services & ViewModels**: Implement `ApiService`, `SignalRService`, `GameStateService`, `LobbyViewModel`, and `GameBoardViewModel` under `SlipItIn/` using `CommunityToolkit.Mvvm` and `WeakReferenceMessenger`. (Anchor: `SlipItIn/`, pending client phase 3 completion).
-- **Offline Action Queue & Auto-Resync**: Implement exponential backoff reconnect logic (0s, 2s, 10s, 30s) and queued action execution upon app resume in MAUI client. (Anchor: `SlipItIn/Services/`, deferred until MAUI service layer setup).
 - **Timer Engine for Slip Rounds**: Background timer service on server enforcing round duration limits (30-60s) with automated round completion notifications. (Anchor: `SlipItIn.Server/Services/`, pending phase 2b refinement).

openwiki/source-map.md

@@ -1,8 +1,14 @@
 ---
 type: Reference
 title: Source Code Map & Navigation Directory
-description: Practical navigation guide mapping source files across projects to system domains and responsibilities.
-tags: [source-map, navigation, directory, projects]
+description: Practical navigation guide mapping source files across projects to system domains, viewmodels, services, and responsibilities.
+tags: [source-map, navigation, directory, projects, maui, mvvm]
+openwiki:
+  roles: [repository]
+  change_kinds: [public-api]
+  source_paths: [SlipItIn/MauiProgram.cs, SlipItIn.Server/Program.cs, SlipItIn.AppHost/AppHost.cs]
+  symbols: [MauiProgram, Program, AppHost]
+  validation_commands: ["dotnet build SlipItIn.slnx"]
 ---
 
 # Source Code Map & Navigation Directory
@@ -19,9 +25,9 @@ This navigation map [indexes backend architecture files described in](/openwiki/
 SlipItIn.slnx
 ├── SlipItIn.AppHost/          # Aspire distributed orchestrator
 ├── SlipItIn.Server/           # Web API & SignalR real-time server
-├── SlipItIn.Shared/           # Shared models & data transfer objects
+├── SlipItIn.Shared/           # Shared models, DTOs & enums
 ├── SlipItIn.ServiceDefaults/  # Aspire OpenTelemetry & health checks
-├── SlipItIn/                  # .NET MAUI multi-platform client
+├── SlipItIn/                  # .NET MAUI multi-platform client (MVVM)
 └── Agents/                    # Architecture & planning briefs
 ```
 
@@ -41,7 +47,7 @@ SlipItIn.slnx
 - **`Controllers/AuthController.cs`**: REST API controller providing `/api/auth/register`, `/api/auth/login`, and `/api/auth/me`. Handles BCrypt password hashing and JWT token generation.
 - **`Hubs/GameHub.cs`**: SignalR hub mapped to `/hubs/game`. Performs JWT claim extraction (`GetAuthenticatedUserId`), player/host authorization checks (`ValidatePlayerAccessAsync`, `ValidateHostAccessAsync`), connection ID tracking, and real-time event broadcasting.
 - **`Services/IGameService.cs`**: Contract interface defining backend game operations.
-- **`Services/GameService.cs`**: Core engine implementation. Handles game creation, player joining, card dealing from active phrases, slip submission, challenge creation, penalty resolution, and state serialization (`GetGameStateAsync`, `GetPlayerHandAsync`).
+- **`Services/GameService.cs`**: Core engine implementation. Handles game creation, player joining, card dealing from active phrases, slip submission, challenge creation, penalty resolution, and state serialization (`GetGameStateAsync`, `GetPlayerHandAsync`). Adds `hostPlayer` directly to `game.Players` before `context.Games.Add(game)` for EF Core navigation safety.
 - **`Data/SlipItInDbContext.cs`**: Entity Framework Core DbContext mapping `Users`, `Games`, `Players`, `Phrases`, `PlayerCards`, `GameRounds`, and `SlipChallenges` to PostgreSQL tables.
 - **`Migrations/`**: Auto-generated EF Core migration snapshots (`20260723193505_InitialCreate.cs`).
 - **`appsettings.json` & `appsettings.Development.json`**: JWT secret keys, issuer/audience defaults, and database connection strings.
@@ -58,12 +64,38 @@ SlipItIn.slnx
 - **`DTOs/GameStateDto.cs`**: DTOs for public state (`GameStateDto`, `PlayerInfoDto`), private hand state (`PlayerHandDto`, `PlayerCardDto`), and challenge alerts (`SlipChallengeDto`).
 
 ### `Cross-Platform MAUI Client` (`SlipItIn`)
-- **`MauiProgram.cs`**: Client builder configuring MAUI app shell, fonts, and logging debug extensions.
+- **`MauiProgram.cs`**: Client app builder. Configures dependency injection for ViewModels and Services, fonts, debug logging, and sets up `ServiceHelper.Services`.
 - **`App.xaml` & `App.xaml.cs`**: Root MAUI application class.
-- **`AppShell.xaml` & `AppShell.xaml.cs`**: AppShell routing container.
-- **`MainPage.xaml` & `MainPage.xaml.cs`**: Initial entry view.
+- **`AppShell.xaml` & `AppShell.xaml.cs`**: Shell navigation container routing between `LoginPage`, `RegisterPage`, `LobbyPage`, and `GameBoardPage`.
+- **`Infrastructure/ServiceHelper.cs`**: Static service locator bridge for runtime DI resolution.
+- **`Services/`**:
+  - `SignalRService.cs` (`ISignalRService`): WebSocket SignalR client, hub method invoker, and auto-reconnect engine.
+  - `GameStateService.cs` (`IGameStateService`): Central game state holder, messenger bridge (`WeakReferenceMessenger`), and offline action queue manager.
+  - `LocalStorageService.cs` (`ILocalStorageService`): Dual-layer local persistence (`SecureStorage` for tokens, `Preferences` for game state/offline queue).
+  - `AuthSessionService.cs` (`IAuthSessionService`): Authenticated user session state manager.
+  - `ApiService.cs` (`IApiService`): REST HTTP client for authentication endpoints.
+  - `AppConfigurationService.cs` (`IAppConfigurationService`): Configuration provider for API base URL and SignalR Hub URL.
+- **`ViewModels/`**:
+  - `BaseViewModel.cs`: Abstract base ViewModel providing `IsBusy`, `StatusMessage`, and error handling helper `RunSafeAsync`.
+  - `LoginViewModel.cs`: Handles email/password authentication and navigation to `LobbyPage`.
+  - `RegisterViewModel.cs`: Handles user registration.
+  - `LobbyViewModel.cs`: Manages lobby creation, joining, player readiness, and game start. Implements `IRecipient` interfaces for real-time messages.
+  - `GameBoardViewModel.cs`: Manages game board state, player cards, slip submission, challenging, challenge resolution, and offline queueing.
+- **`Views/`**:
+  - `LoginPage.xaml` / `.cs`: XAML login UI view.
+  - `RegisterPage.xaml` / `.cs`: XAML registration UI view.
+  - `LobbyPage.xaml` / `.cs`: XAML lobby UI view displaying lobby code and player list.
+  - `GameBoardPage.xaml` / `.cs`: XAML game board UI view displaying cards and player list.
+  - `ChallengeNotificationOverlay.xaml` / `.cs`: Reusable overlay view for challenge alerts.
+- **`Messages/`**:
+  - `LobbyCreatedMessage.cs`, `GameStateChangedMessage.cs`, `GameStartedMessage.cs`, `PlayerHandChangedMessage.cs`, `ChallengeReceivedMessage.cs`, `ErrorOccurredMessage.cs`, `ConnectionStateChangedMessage.cs`: Strongly-typed `CommunityToolkit.Mvvm.Messaging` payloads.
+- **`Models/`**:
+  - `QueuedGameAction.cs`: Data model for offline game action queueing.
 - **`Platforms/`**: Platform-specific entry points for Android, iOS, MacCatalyst, and Windows.
 
 ### `Documentation & Specifications` (`Agents/`)
-- **`Agents/Architecture.md`**: Specification document defining Phase 2b backend security (JWT validation, `IDbContextFactory`, privacy DTOs) and Phase 3b MAUI stability patterns (`WeakReferenceMessenger`, auto-reconnect, dual-layer storage).
-- **`Agents/ProjectPlan.md`**: Project plan breakdown covering phases 1 through 4.
+- **`Agents/Architecture.md`**: Specification document defining backend security and client MVVM/stability patterns.
+- **`Agents/ProjectPlan.md`**: Project plan breakdown covering development phases.
+
+### `Automation & CI/CD` (`.github/workflows/`)
+- **`.github/workflows/openwiki-update.yml`**: Scheduled GitHub Actions workflow executing `openwiki code --update` via Gemini Flash (`gemini-3.6-flash`) to keep repository documentation in sync with source changes.

openwiki/workflows/index.md

@@ -1,3 +1,3 @@
 # Files
 
-- [Slip & Challenge Workflows](slip-and-challenge.md) - Real-time game loops covering lobby creation, card dealing, phrase slipping, slip challenging, and challenge resolution.
+- [Slip & Challenge Workflows](slip-and-challenge.md) - Real-time game loops covering authentication, lobby creation, card dealing, phrase slipping, slip challenging, challenge resolution, and offline action queuing.

openwiki/workflows/slip-and-challenge.md

@@ -1,121 +1,175 @@
 ---
 type: Workflow
 title: Slip & Challenge Workflows
-description: Real-time game loops covering lobby creation, card dealing, phrase slipping, slip challenging, and challenge resolution.
-tags: [workflow, game-loop, signalr, slip-mechanic, real-time]
+description: Real-time game loops covering authentication, lobby creation, card dealing, phrase slipping, slip challenging, challenge resolution, and offline action queuing.
+tags: [workflow, game-loop, signalr, slip-mechanic, real-time, offline-resync]
+openwiki:
+  roles: [workflow]
+  change_kinds: [public-api, lifecycle]
+  source_paths: [SlipItIn/ViewModels/GameBoardViewModel.cs, SlipItIn/Services/GameStateService.cs, SlipItIn/Services/SignalRService.cs, SlipItIn.Server/Hubs/GameHub.cs]
+  symbols: [LobbyViewModel, GameBoardViewModel, SignalRService, GameStateService, GameHub]
+  validation_commands: ["dotnet build SlipItIn.slnx"]
 ---
 
 # Slip & Challenge Workflows
 
-This document outlines the core real-time game workflows in SlipItIn, detailing how SignalR events, backend service operations, database updates, and client state notifications interact.
+This document outlines the core real-time game workflows in SlipItIn, detailing how client MVVM ViewModels, `WeakReferenceMessenger`, backend SignalR hubs, database services, and offline action queues interact.
 
-These workflows [execute state transitions on](/openwiki/domain/game-mechanics.md) domain entities, [invoke real-time methods in](/openwiki/architecture/overview.md) the ASP.NET Core `GameHub`, [are implemented across backend services mapped in](/openwiki/source-map.md) the source map, and [are verified using tests described in](/openwiki/operations/runbook.md) the operations runbook.
+These workflows [execute state transitions on](/openwiki/domain/game-mechanics.md) domain entities, [invoke real-time methods in](/openwiki/architecture/overview.md) the ASP.NET Core `GameHub` and client `SignalRService`, [are implemented across backend and client services mapped in](/openwiki/source-map.md) the source map, and [are verified using tests described in](/openwiki/operations/runbook.md) the operations runbook.
 
 ---
 
 ## 1. Game Setup & Lobby Workflow
 
 ```
-[Host] CreateLobby() ──> Generate 6-Char LobbyCode ──> Add to SignalR Group
-                                                               │
-[Player] JoinLobby() ──> Verify MaxPlayers & Status ───────────┤
-                                                               │
-[Player] PlayerReady() ──> Set IsReady = true ─────────────────┼──> Broadcast GameStateUpdated
-                                                               │
-[Host] StartGame() ──> Deal 5 Random Cards Per Player ─────────┴──> Unicast PlayerHandUpdated
+[Client App] LoginVM.LoginAsync() ──> REST Auth ──> Save Token in SecureStorage ──> SignalR.ConnectAsync()
+                                                                                             │
+[Host] LobbyVM.CreateLobbyAsync() ──> SignalR.CreateLobbyAsync() ──> Server Generates Code ──┤
+                                                                                             │
+[Player] LobbyVM.JoinLobbyAsync() ──> SignalR.JoinLobbyAsync(code) ──────────────────────────┤
+                                                                                             │
+[Player] LobbyVM.SetReadyAsync() ──> SignalR.PlayerReadyAsync() ─────────────────────────────┼──> Broadcast GameStateUpdated
+                                                                                             │
+[Host] LobbyVM.StartGameAsync() ──> SignalR.StartGameAsync() ──> Deal 5 Cards / Player ──────┴──> Unicast PlayerHandUpdated
 ```
 
-1. **Lobby Creation**: Host calls `GameHub.CreateLobby()`. `GameService.CreateGameAsync()` creates a `Game` record (`Status = Lobby`), generates a random 6-character `LobbyCode`, adds the host as the first `Player`, and registers the host's WebSocket `ConnectionId`. Caller receives `LobbyCreated`.
-2. **Joining Lobby**: Opponents invoke `GameHub.JoinLobby(lobbyCode)`. `GameService.JoinGameAsync()` validates that the game exists, has space (`Players.Count < MaxPlayers`), and is in `Lobby` status. The player is assigned a `Player` entry, added to the SignalR group `lobbyCode`, and `PlayerJoined` (`GameStateDto`) is broadcast to all participants.
-3. **Player Ready**: Players invoke `GameHub.PlayerReady(gameId, playerId)`. `GameHub` checks `ValidatePlayerAccessAsync` and broadcasts `GameStateUpdated`.
-4. **Game Start & Card Dealing**: The host invokes `GameHub.StartGame(gameId)`. `GameHub` verifies host authorization via `ValidateHostAccessAsync(gameId, authUserId)`.
+1. **Authentication & Session Setup**: Player logs in via `LoginPage` (`LoginViewModel.LoginAsync()`). `ApiService` posts credentials to `/api/auth/login`. `AuthSessionService` persists the token to `SecureStorage`. `SignalRService.ConnectAsync(token)` opens a WebSocket connection to `/hubs/game`.
+2. **Lobby Creation**: Host invokes `LobbyViewModel.CreateLobbyAsync()`. `SignalRService.CreateLobbyAsync()` triggers `GameHub.CreateLobby()`. `GameService.CreateGameAsync()` creates a `Game` record (`Status = Lobby`), generates a random 6-character `LobbyCode`, adds host to `game.Players`, and registers host's `ConnectionId`. Caller receives `LobbyCreated` message via `WeakReferenceMessenger`.
+3. **Joining Lobby**: Opponents call `LobbyViewModel.JoinLobbyAsync()`. `SignalRService.JoinLobbyAsync(code)` validates game status and capacity. `GameService.JoinGameAsync()` assigns player to game, registers `ConnectionId`, adds player to SignalR group `lobbyCode`, and broadcasts `PlayerJoined` (`GameStateDto`) to all participants.
+4. **Player Ready**: Players invoke `LobbyViewModel.SetReadyAsync()`. `GameHub.PlayerReady()` verifies access and broadcasts `GameStateUpdated`.
+5. **Game Start & Card Dealing**: The host invokes `LobbyViewModel.StartGameAsync()`.
+   - `GameHub.StartGame()` verifies host identity (`ValidateHostAccessAsync`).
    - `GameService.StartGameAsync()` transitions `GameStatus` to `InProgress` and creates `GameRound` 1 (`RoundStatus.Active`).
-   - `GameService.DealCardsAsync()` fetches active phrases, randomly selects 5 phrases per player, creates `PlayerCard` entries, and saves them to PostgreSQL.
-   - SignalR broadcasts `GameStarted` to the group.
+   - `GameService.DealCardsAsync()` selects 5 random phrases per player, creates `PlayerCard` records, and saves them to PostgreSQL.
+   - SignalR broadcasts `GameStarted` to the group (triggering client navigation to `GameBoardPage`).
    - SignalR sends private `PlayerHandUpdated` notifications (`PlayerHandDto`) individually to each player's `ConnectionId`.
 
 ---
 
-## 2. Phrase Slipping Workflow
+## 2. Phrase Slipping & Offline Queueing Workflow
 
 During real-life conversation or chat, a player speaks or types one of their secret phrases and marks it as used in the app:
 
-1. **Submission**: Player A calls `GameHub.SubmitSlip(gameId, playerId, cardId)`.
-2. **Access Control**: `GameHub` executes `ValidatePlayerAccessAsync(playerId, userId)` to verify that Player A owns the specified `Player` account.
-3. **Engine Execution**: `GameService.SubmitSlipAsync()` loads the `PlayerCard`, validates card ownership (`card.PlayerId == playerId`), and sets `card.IsUsed = true`.
-4. **Notification**: `GameHub` broadcasts `SlipSubmitted` (`{ PlayerId, CardId, Success }`) to the SignalR lobby group.
+1. **User Action**: Player clicks **Submit Slip** on `GameBoardPage` (`GameBoardViewModel.SubmitSlipAsync(card)`).
+2. **Online / Offline Branching**:
+   - **If Connected (`_signalR.IsConnected`)**: Calls `SignalRService.SubmitSlipAsync(gameId, playerId, cardId)` directly. `GameHub.SubmitSlip()` validates ownership and updates `PlayerCard.IsUsed = true`. `GameHub` broadcasts `SlipSubmitted` to the lobby group.
+   - **If Offline (`!_signalR.IsConnected`)**: Calls `GameStateService.EnqueueActionAsync("SubmitSlip", gameId, playerId, cardId)`. Action is serialized into `QueuedGameAction` and saved in `Preferences`. UI updates status to `"Offline: Aktion wurde zwischengespeichert."`
 
 ---
 
 ## 3. Slip Challenge & Resolution Workflow
 
-If another player suspects that a submitted phrase or recent conversation statement was an invalid slip, they can challenge the slipper.
+If an opponent suspects that a submitted phrase or recent conversation statement was an invalid slip, they can challenge the slipper.
 
 ### Step 1: Challenge Initiation
-1. Player B (Challenger) calls `GameHub.ChallengeSlip(gameId, challengingPlayerId, targetCardId)`.
-2. `GameHub` verifies Player B's identity (`ValidatePlayerAccessAsync`).
-3. `GameService.CreateChallengeAsync()` creates a `SlipChallenge` entity with `ChallengeStatus.Pending`.
-4. `GameHub` broadcasts `SlipChallenged` (`SlipChallengeDto`) to the lobby group.
-5. `GameHub` sends a targeted `ChallengeReceived` message directly to Player A's `ConnectionId`.
+1. Challenger clicks **Challenge** on `GameBoardPage` (`GameBoardViewModel.ChallengeCardAsync(card)`).
+2. If online, calls `SignalRService.ChallengeSlipAsync(gameId, playerId, cardId)`.
+3. `GameHub.ChallengeSlip()` verifies challenger identity (`ValidatePlayerAccessAsync`).
+4. `GameService.CreateChallengeAsync()` creates a `SlipChallenge` entity with `ChallengeStatus.Pending`.
+5. `GameHub` broadcasts `SlipChallenged` (`SlipChallengeDto`) to the group and unicasts `ChallengeReceived` directly to target player's `ConnectionId`.
+6. Client target player sees `ChallengeNotificationOverlay` on `GameBoardPage`.
 
 ### Step 2: Challenge Resolution
-Player A (the accused) responds by admitting or denying the false slip:
+The accused player responds via `ChallengeNotificationOverlay`:
 
-1. Player A calls `GameHub.ResolveChallenge(challengeId, approved)`.
-2. `GameHub` executes `ValidateChallengeTargetAccessAsync(challengeId, authUserId)` to guarantee that *only* the accused player can resolve the challenge.
-3. `GameService.ResolveChallengeAsync()` executes penalty logic:
-   - **`approved = true` (Justified Accusation / Legitimate Catch)**: The accused admits the phrase was a fake slip. `SlipChallenge.Status` is set to `Approved`. The card remains with the accused player.
-   - **`approved = false` (False Accusation / Wrong Penalty)**: The accused denies the charge (the slip was valid). `SlipChallenge.Status` is set to `Rejected`. As a penalty for making a false accusation, the phrase card is reassigned to the challenger: `targetCard.PlayerId = challenge.ChallengingPlayerId`. The challenger now holds >5 cards in their hand.
-4. `GameHub` broadcasts `ChallengeResolved` to the lobby group.
-
-### Real-time Sequence Diagram
+1. Accused player calls `GameBoardViewModel.ResolveChallengeAsync(challengeId, approved)`.
+2. `SignalRService.ResolveChallengeAsync(challengeId, approved)` calls `GameHub.ResolveChallenge()`.
+3. `GameHub` executes `ValidateChallengeTargetAccessAsync(challengeId, authUserId)` to guarantee *only* the accused player can resolve the challenge.
+4. `GameService.ResolveChallengeAsync()` executes penalty logic:
+   - **`approved = true` (Justified Accusation / Legitimate Catch)**: The accused admits the phrase was a fake slip. `SlipChallenge.Status` is set to `Approved`. The card remains with accused player.
+   - **`approved = false` (False Accusation / Wrong Penalty)**: The accused denies the charge. `SlipChallenge.Status` is set to `Rejected`. As a penalty for making a false accusation, the phrase card is reassigned to the challenger: `targetCard.PlayerId = challenge.ChallengingPlayerId`.
+5. `GameHub` broadcasts `ChallengeResolved` to the group.
 
 ```mermaid
 sequenceDiagram
     autonumber
-    actor Slipper as Player A (Accused)
-    actor Challenger as Player B (Challenger)
+    actor Slipper as Accused Player A
+    actor Challenger as Challenger Player B
+    participant GameBoardVM as GameBoardViewModel
     participant Hub as GameHub
     participant Service as GameService
     participant DB as SlipItInDbContext
 
     Note over Slipper, Challenger: Active Gameplay
-    Slipper->>Hub: SubmitSlip(gameId, playerAId, cardId)
-    Hub->>Service: SubmitSlipAsync(gameId, playerAId, cardId)
+    Slipper->>GameBoardVM: SubmitSlipAsync(card)
+    GameBoardVM->>Hub: SubmitSlip(gameId, playerAId, cardId)
+    Hub->>Service: SubmitSlipAsync()
     Service->>DB: Set PlayerCard.IsUsed = true
-    Hub-->>Challenger: Broadcast "SlipSubmitted"
+    Hub-->>Challenger: Broadcast SlipSubmitted
 
     Note over Challenger: Suspects invalid phrase
-    Challenger->>Hub: ChallengeSlip(gameId, playerBId, targetCardId)
+    Challenger->>GameBoardVM: ChallengeCardAsync(card)
+    GameBoardVM->>Hub: ChallengeSlip(gameId, playerBId, cardId)
     Hub->>Service: CreateChallengeAsync()
     Service->>DB: Insert SlipChallenge (Status = Pending)
-    Hub-->>Challenger: Broadcast "SlipChallenged" (SlipChallengeDto)
-    Hub-->>Slipper: Unicast "ChallengeReceived" to ConnectionId
+    Hub-->>Challenger: Broadcast SlipChallenged
+    Hub-->>Slipper: Unicast ChallengeReceived
 
-    Note over Slipper: Accused resolves accusation
-    Slipper->>Hub: ResolveChallenge(challengeId, approved)
+    Note over Slipper: Notification Overlay Displays
+    Slipper->>GameBoardVM: ResolveChallengeAsync(challengeId, approved)
+    GameBoardVM->>Hub: ResolveChallenge(challengeId, approved)
     Hub->>Hub: ValidateChallengeTargetAccessAsync()
-    Hub->>Service: ResolveChallengeAsync(challengeId, approved)
+    Hub->>Service: ResolveChallengeAsync()
     alt approved == false (False Accusation)
-        Service->>DB: Update targetCard.PlayerId = PlayerBId (Penalty)
+        Service->>DB: Reassign card.PlayerId = PlayerBId
         Service->>DB: Set Challenge.Status = Rejected
     else approved == true (Justified Catch)
         Service->>DB: Set Challenge.Status = Approved
     end
-    Hub-->>Challenger: Broadcast "ChallengeResolved"
+    Hub-->>Challenger: Broadcast ChallengeResolved
 ```
+*Sequence diagram showing phrase submission, challenge initiation, target notification, and penalty resolution.*
 
 ---
 
-## 4. SignalR Hub Event Reference
+## 4. Offline Action Queueing & Reconnection Resync Workflow
 
-Summary of server-to-client events emitted by `GameHub.cs`:
+When network connection is temporarily interrupted during gameplay, SlipItIn ensures action durability and smooth state synchronization:
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor User as Player
+    participant GameBoardVM as GameBoardViewModel
+    participant GameStateSvc as GameStateService
+    participant LocalStorage as LocalStorageService
+    participant SignalRSvc as SignalRService
+    participant Hub as GameHub
+
+    Note over User, SignalRSvc: Network Disconnected (Offline)
+    User->>GameBoardVM: SubmitSlipAsync(card)
+    GameBoardVM->>GameStateSvc: EnqueueActionAsync("SubmitSlip", args)
+    GameStateSvc->>LocalStorage: SaveQueuedActionsAsync(queuedList)
+    LocalStorage-->>GameBoardVM: Saved to Preferences
+
+    Note over SignalRSvc: Network Restored
+    SignalRSvc->>Hub: Automatic Reconnect (Exponential Backoff)
+    SignalRSvc->>GameStateSvc: ConnectionStateChanged(true)
+    GameStateSvc->>GameStateSvc: ResyncAsync()
+    GameStateSvc->>SignalRSvc: RequestGameStateAsync(gameId)
+    SignalRSvc->>Hub: RequestGameState(gameId)
+    Hub-->>GameStateSvc: GameStateUpdated (Fresh DTO)
+
+    GameStateSvc->>GameStateSvc: FlushQueuedActionsAsync()
+    loop For each QueuedGameAction
+        GameStateSvc->>SignalRSvc: SendQueuedActionAsync(action)
+        SignalRSvc->>Hub: InvokeCoreAsync(action.Method, action.Args)
+    end
+    GameStateSvc->>LocalStorage: ClearQueuedActionsAsync()
+```
+*Sequence diagram showing offline action queueing in local preferences, automatic reconnection, state request, and queued action replay.*
+
+---
+
+## 5. SignalR Hub Event Reference
+
+Summary of server-to-client events emitted by `GameHub.cs` and handled by `SignalRService`:
 
 | Event Name | Scope | Payload | Trigger |
 |---|---|---|---|
 | `LobbyCreated` | Caller | `{ GameId, LobbyCode }` | Host calls `CreateLobby()` |
 | `PlayerJoined` | Group | `GameStateDto` | Player calls `JoinLobby()` |
-| `GameStateUpdated` | Group | `GameStateDto` | Player calls `PlayerReady()` |
+| `GameStateUpdated` | Group | `GameStateDto` | Player calls `PlayerReady()` or `RequestGameState()` |
 | `GameStarted` | Group | `{ GameId }` | Host calls `StartGame()` |
 | `PlayerHandUpdated` | Unicast | `PlayerHandDto` | Hand dealt or updated |
 | `SlipSubmitted` | Group | `{ PlayerId, CardId, Success }` | Player calls `SubmitSlip()` |
@@ -123,3 +177,21 @@ Summary of server-to-client events emitted by `GameHub.cs`:
 | `ChallengeReceived` | Unicast | `SlipChallengeDto` | Direct alert to target player |
 | `ChallengeResolved` | Group | `SlipChallengeDto` | Target calls `ResolveChallenge()` |
 | `Error` | Caller | `{ Message }` | Any authorization or engine exception |
+
+---
+
+## 6. Guidance for Future Agents & Developers
+
+- **When to Consult**: Refer to this document when adding new game interactions, modifying UI challenge flows, changing reconnection strategies, or replaying offline actions.
+- **Invariants**:
+  - `FlushQueuedActionsAsync()` MUST execute in strictly sequential order based on `CreatedAtUtc`.
+  - `ResolveChallenge` MUST throw `UnauthorizedAccessException` if invoked by anyone other than the target player.
+- **Primary Source Files**:
+  - `SlipItIn/ViewModels/GameBoardViewModel.cs`
+  - `SlipItIn/Services/GameStateService.cs`
+  - `SlipItIn/Services/SignalRService.cs`
+  - `SlipItIn.Server/Hubs/GameHub.cs`
+- **Minimal Validation Command**:
+  ```bash
+  dotnet build SlipItIn.slnx
+  ```