Add Shop system with ShopManager, ShopUI, and ShopSlotUI; implement item purchasing and shop UI functionality

Assets/Scripts/Systems/EnemyDeathBehavior.cs

@@ -1,15 +1,21 @@
 using Interfaces;
+using Sirenix.Serialization;
 using UnityEngine;
 
 namespace Systems
 {
     public class EnemyDeathBehavior : MonoBehaviour, IDeathBehavior
     {
+        [OdinSerialize, SerializeField] private int expReward = 5;
+        [OdinSerialize, SerializeField] private int coinReward = 1;
+        
         public void Die()
         {
+            GameManager.Instance.Player.attributes.ModifyExperience(expReward);
+            GameManager.Instance.AddCoins(coinReward);
             Destroy(gameObject);
+            
             // later let's add particle effects, sound effects, etc.
-            // and give player experience points
         }
     }
 }