refactor: Consolidate skill component logic into SkillComponentBase and update manager access to singletons.

Autoloads/SaveSystem.cs

@@ -14,12 +14,24 @@ public partial class SaveSystem : Node
     [Export] public string SavePath { get; set; } = "user://savegame.json";
     [Export] public int Version { get; set; } = 2;
 
+    public static SaveSystem Instance { get; private set; }
+
     private static readonly JsonSerializerOptions JsonOptions = new()
     {
         WriteIndented = true,
         PropertyNamingPolicy = JsonNamingPolicy.CamelCase
     };
 
+    public override void _Ready()
+    {
+        Instance = this;
+    }
+
+    public override void _ExitTree()
+    {
+        if (Instance == this) Instance = null;
+    }
+
     public void SaveGame()
     {
         var store = GameStateStore.Instance;