fix(lobby): ready status anzeigen und Spielstart absichern

SlipItIn.Server/Hubs/GameHub.cs

@@ -110,6 +110,8 @@ public class GameHub : Hub
             await Groups.AddToGroupAsync(connectionId, game.LobbyCode);
 
             await Clients.Caller.SendAsync("LobbyCreated", new { GameId = game.Id, LobbyCode = game.LobbyCode });
+            var gameState = await _gameService.GetGameStateAsync(game.Id);
+            await Clients.Caller.SendAsync("PlayerJoined", gameState);
             _logger.LogInformation("Lobby {LobbyCode} created by user {UserId}", game.LobbyCode, userId);
         }
         catch (UnauthorizedAccessException)

SlipItIn.Server/Services/GameService.cs

@@ -81,6 +81,9 @@ public class GameService : IGameService
         if (game.Players.Count < 2)
             throw new InvalidOperationException("At least 2 players are required to start the game");
 
+        if (game.Players.Any(player => !player.IsReady))
+            throw new InvalidOperationException("All players must be ready to start the game");
+
         game.Status = GameStatus.InProgress;
         game.StartedAt = DateTime.UtcNow;