feat: 빈사/부활 시스템 및 ReviveEffect 추가

- PlayerNetworkController에 Revive(healthPercent) 메서드와 OnRevived 이벤트 추가

- ReviveEffect 스킬 이펙트 구현 (Area/Ally 타겟팅, healthPercent로 체력 복구)

- GameManager가 OnRevived 구독하여 alivePlayers 동적 복구

- GameManager.Update에서 나중에 스폰된 플레이어 자동 구독 (MPP 대응)

- SkillCancelReason에 Revive 추가

- 부활 스킬/이펙트 ScriptableObject 에셋 생성 (치유 클립 임시 사용)

- PlayerSkillDebugMenu에 즉사/부활/리스폰/스폰/Client1 스킬 디버그 메뉴 추가

- PlayerAbnormalityDebugHUD에 부활 버튼 추가

- DebugExecuteSkillAsServer에 실패 원인 로그 추가

- AGENTS.md에 코드 변경 후 force reload 규칙 추가

Assets/_Game/Scripts/Core/GameManager.cs

@@ -356,6 +356,7 @@ namespace Colosseum
         #region Player Death Tracking
 
         private List<PlayerNetworkController> alivePlayers = new List<PlayerNetworkController>();
+        private HashSet<PlayerNetworkController> subscribedPlayers = new HashSet<PlayerNetworkController>();
 
         private IEnumerator WaitForPlayersAndSubscribe()
         {
@@ -373,16 +374,27 @@ namespace Colosseum
             var players = FindObjectsByType<PlayerNetworkController>(FindObjectsSortMode.None);
             foreach (var player in players)
             {
-                player.OnDeath += HandlePlayerDeath;
-                if (!player.IsDead)
-                {
-                    alivePlayers.Add(player);
-                }
+                SubscribeSinglePlayer(player);
             }
 
             if (debugMode)
             {
-                Debug.Log($"[GameManager] Subscribed to {players.Length} players, {alivePlayers.Count} alive");
+                Debug.Log($"[GameManager] Subscribed to {subscribedPlayers.Count} players, {alivePlayers.Count} alive");
+            }
+        }
+
+        private void SubscribeSinglePlayer(PlayerNetworkController player)
+        {
+            if (player == null || subscribedPlayers.Contains(player))
+                return;
+
+            player.OnDeath += HandlePlayerDeath;
+            player.OnRevived += HandlePlayerRevived;
+            subscribedPlayers.Add(player);
+
+            if (!player.IsDead)
+            {
+                alivePlayers.Add(player);
             }
         }
 
@@ -392,8 +404,25 @@ namespace Colosseum
             foreach (var player in players)
             {
                 player.OnDeath -= HandlePlayerDeath;
+                player.OnRevived -= HandlePlayerRevived;
             }
             alivePlayers.Clear();
+            subscribedPlayers.Clear();
+        }
+
+        /// <summary>
+        /// MPP 등으로 나중에 스폰된 플레이어를 동적으로 감지하여 구독합니다.
+        /// </summary>
+        private void Update()
+        {
+            if (!IsServer || currentState.Value != GameState.Playing)
+                return;
+
+            var players = FindObjectsByType<PlayerNetworkController>(FindObjectsSortMode.None);
+            for (int i = 0; i < players.Length; i++)
+            {
+                SubscribeSinglePlayer(players[i]);
+            }
         }
 
         private void HandlePlayerDeath(PlayerNetworkController player)
@@ -412,6 +441,19 @@ namespace Colosseum
             }
         }
 
+        private void HandlePlayerRevived(PlayerNetworkController player)
+        {
+            if (alivePlayers.Contains(player))
+                return;
+
+            alivePlayers.Add(player);
+
+            if (debugMode)
+            {
+                Debug.Log($"[GameManager] Player revived. Alive: {alivePlayers.Count}");
+            }
+        }
+
         #endregion
 
         #region Boss Death Tracking