[Combat] IDamageable 인터페이스 적용으로 대미지 시스템 일원화

- PlayerNetworkController에 IDamageable 인터페이스 구현
- DamageEffect, HealEffect가 IDamageable 사용하도록 변경
- 플레이어와 보스 모두에게 대미지/힐 적용 가능

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Assets/Scripts/Player/PlayerNetworkController.cs

@@ -1,13 +1,15 @@
+using System;
 using UnityEngine;
 using Unity.Netcode;
 using Colosseum.Stats;
+using Colosseum.Combat;
 
 namespace Colosseum.Player
 {
     /// <summary>
     /// 플레이어 네트워크 상태 관리 (HP, MP 등)
     /// </summary>
-    public class PlayerNetworkController : NetworkBehaviour
+    public class PlayerNetworkController : NetworkBehaviour, IDamageable
     {
         [Header("References")]
         [Tooltip("CharacterStats 컴포넌트 (없으면 자동 검색)")]
@@ -23,6 +25,14 @@ namespace Colosseum.Player
         public float MaxMana => characterStats != null ? characterStats.MaxMana : 50f;
         public CharacterStats Stats => characterStats;
 
+        // 체력/마나 변경 이벤트
+        public event Action<float, float> OnHealthChanged; // (oldValue, newValue)
+        public event Action<float, float> OnManaChanged; // (oldValue, newValue)
+
+        // IDamageable 구현
+        public float CurrentHealth => currentHealth.Value;
+        public bool IsDead => currentHealth.Value <= 0f;
+
         public override void OnNetworkSpawn()
         {
             // CharacterStats 참조 확인
@@ -31,6 +41,10 @@ namespace Colosseum.Player
                 characterStats = GetComponent<CharacterStats>();
             }
 
+            // 네트워크 변수 변경 콜백 등록
+            currentHealth.OnValueChanged += HandleHealthChanged;
+            currentMana.OnValueChanged += HandleManaChanged;
+
             // 초기화
             if (IsServer)
             {
@@ -39,6 +53,23 @@ namespace Colosseum.Player
             }
         }
 
+        public override void OnNetworkDespawn()
+        {
+            // 콜백 해제
+            currentHealth.OnValueChanged -= HandleHealthChanged;
+            currentMana.OnValueChanged -= HandleManaChanged;
+        }
+
+        private void HandleHealthChanged(float oldValue, float newValue)
+        {
+            OnHealthChanged?.Invoke(oldValue, newValue);
+        }
+
+        private void HandleManaChanged(float oldValue, float newValue)
+        {
+            OnManaChanged?.Invoke(oldValue, newValue);
+        }
+
         /// <summary>
         /// 대미지 적용 (서버에서만 실행)
         /// </summary>
@@ -85,5 +116,38 @@ namespace Colosseum.Player
             // TODO: 사망 처리 로직
             Debug.Log($"Player {OwnerClientId} died!");
         }
+
+        #region IDamageable
+        /// <summary>
+        /// 대미지 적용 (서버에서만 호출)
+        /// </summary>
+        public float TakeDamage(float damage, object source = null)
+        {
+            if (!IsServer) return 0f;
+
+            float actualDamage = Mathf.Min(damage, currentHealth.Value);
+            currentHealth.Value = Mathf.Max(0f, currentHealth.Value - damage);
+
+            if (currentHealth.Value <= 0f)
+            {
+                HandleDeath();
+            }
+
+            return actualDamage;
+        }
+
+        /// <summary>
+        /// 체력 회복 (서버에서만 호출)
+        /// </summary>
+        public float Heal(float amount)
+        {
+            if (!IsServer) return 0f;
+
+            float actualHeal = Mathf.Min(amount, MaxHealth - currentHealth.Value);
+            currentHealth.Value = Mathf.Min(MaxHealth, currentHealth.Value + amount);
+
+            return actualHeal;
+        }
+        #endregion
     }
 }