Cleanup compile warnings, cleanup logs, spruce up level selection menu

Assets/Scripts/Data/CardSystem/CardSystemManager.cs

@@ -19,7 +19,6 @@ namespace Data.CardSystem
     public class CardSystemManager : MonoBehaviour
     {
         private static CardSystemManager _instance;
-        private static bool _isQuitting = false;
         public static CardSystemManager Instance => _instance;
         
         [Header("Card Collection")]
@@ -56,11 +55,6 @@ namespace Data.CardSystem
             Logging.Debug("[CardSystemManager] Post-boot initialization complete");
         }
 
-        private void OnApplicationQuit()
-        {
-            _isQuitting = true;
-        }
-
         /// <summary>
         /// Loads all card definitions from Addressables using the "BlokkemonCard" label
         /// </summary>