fix: simplify finishGame to not require userId — first caller wins

app/src/main/java/app/closer/domain/usecase/GameSessionManager.kt

@@ -94,23 +94,20 @@ class GameSessionManager @Inject constructor(
     }
 
     /**
-     * Finish the session referenced by [handle] for the current user.
+     * Finish the session referenced by [handle].
      */
-    suspend fun finishGameForCurrentUser(handle: GameHandle): Result<Unit> {
-        val userId = authRepository.currentUserId
-            ?: return Result.failure(Exception("Not signed in"))
-        return finishGame(handle.sessionId, handle.coupleId, userId)
-    }
+    suspend fun finishGameForCurrentUser(handle: GameHandle): Result<Unit> =
+        finishGame(handle.sessionId, handle.coupleId)
 
     /**
-     * Finish the current session for a user.
-     * Marks the session as completed by this user.
-     * Notifies partner when both users have completed.
+     * Mark the session as completed for the couple.
+     * The first caller wins — the whole session flips to "completed" immediately.
+     * This is correct for pass-the-phone games; async partner-sync games would
+     * need per-user completion fields instead.
      */
     suspend fun finishGame(
         sessionId: String,
-        coupleId: String,
-        userId: String
+        coupleId: String
     ): Result<Unit> = runCatching {
         val currentSession = sessionRepository.getActiveSessionForCouple(coupleId)
             ?: throw Exception("No active session found")

app/src/main/java/app/closer/ui/wheel/WheelCompleteScreen.kt

@@ -69,8 +69,7 @@ class WheelCompleteViewModel @Inject constructor(
             val couple = coupleRepository.getCoupleForUser(uid) ?: return@launch
             gameSessionManager.finishGame(
                 sessionId = sessionId,
-                coupleId = couple.id,
-                userId = uid
+                coupleId = couple.id
             )
         }
     }