fix: disable turn validation in arcade mode matching game

Removed turn validation check that was causing "Not your turn" errors.
The validator was comparing player numbers (1, 2, 3) with viewer UUIDs,
which never matched. In arcade mode, a single user controls all players,
so turn validation is not applicable.

- Removed comparison of state.currentPlayer (number) vs playerId (UUID)
- Allows single user to flip cards for any player in arcade mode
- Fixes card flipping functionality in matching game

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/lib/arcade/validation/MatchingGameValidator.ts

@@ -45,13 +45,11 @@ export class MatchingGameValidator implements GameValidator<MemoryPairsState, Ma
       }
     }
 
-    // Check if it's the player's turn (in multiplayer)
-    if (state.activePlayers.length > 1 && state.currentPlayer.toString() !== playerId) {
-      return {
-        valid: false,
-        error: 'Not your turn',
-      }
-    }
+    // Skip turn validation in arcade mode where a single user controls multiple players
+    // In this case, playerId is the viewer ID (UUID), not a player number
+    // Turn validation only applies to true multiplayer with different users
+    // Since we can't distinguish here, we disable turn validation for arcade sessions
+    // (A better solution would be to pass both viewerId and playerNumber in moves)
 
     // Find the card
     const card = state.gameCards.find(c => c.id === cardId)