fixed for cooperate mode

src/gameplay/coop/CoopGame.h

@@ -57,7 +57,9 @@ public:
 
     explicit CoopGame(int startLevel = 0);
     using SoundCallback = std::function<void(int)>;
+    using LevelUpCallback = std::function<void(int)>;
     void setSoundCallback(SoundCallback cb) { soundCallback = cb; }
+    void setLevelUpCallback(LevelUpCallback cb) { levelUpCallback = cb; }
 
     void reset(int startLevel = 0);
     void tickGravity(double frameMs);
@@ -137,6 +139,7 @@ private:
     uint32_t hardDropFxId{0};
     uint64_t pieceSequence{0};
     SoundCallback soundCallback;
+    LevelUpCallback levelUpCallback;
 
     // Helpers ---------------------------------------------------------------
     PlayerState& player(PlayerSide s) { return s == PlayerSide::Left ? left : right; }