Implement health modification on enemy kill; add HealOnKillModifier and update death behavior

Assets/Scripts/Systems/CharacterModifierManager.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using Data;
 using Interfaces;
@@ -10,20 +11,50 @@ namespace Systems
     public class CharacterModifierManager : MonoBehaviour
     {
         [OdinSerialize] private List<IStatModifier> activeModifiers = new();
+        [OdinSerialize] private List<IOnKillEffect> onKillEffects = new();
         
         [SerializeField, Self] private Character character;
-        
+
+        private void OnEnable()
+        {
+            EnemyDeathBehavior.OnAnyEnemyKilled += HandleEnemyKilled;
+        }
+
+        private void OnDisable()
+        {
+            EnemyDeathBehavior.OnAnyEnemyKilled -= HandleEnemyKilled;
+        }
+
         public void EquipItem(IStatModifier modifier)
         {
             activeModifiers.Add(modifier);
             modifier.Apply(character.attributes);
+            
+            if (modifier is IOnKillEffect onKillEffect)
+            {
+                onKillEffects.Add(onKillEffect);
+            }
         }
         
         public void UnequipItem(IStatModifier modifier)
         {
-            if (activeModifiers.Remove(modifier))
+            if (!activeModifiers.Remove(modifier)) return;
+            
+            modifier.Remove(character.attributes);
+                
+            if (modifier is IOnKillEffect onKillEffect)
             {
-                modifier.Remove(character.attributes);
+                onKillEffects.Remove(onKillEffect);
+            }
+        }
+
+        private void HandleEnemyKilled(GameObject killer, GameObject victim)
+        {
+            if (killer != gameObject) return;
+
+            foreach (var effect in onKillEffects)
+            {
+                effect.OnKill(killer, victim);
             }
         }
     }