Add game scene and level catalog interfaces, and implement scene management in AppRoot

features/ui/menus/MainMenu.cs

@@ -1,6 +1,7 @@
 using Chickensoft.AutoInject;
 using Chickensoft.Introspection;
 using Godot;
+using Mr.BrickAdventures.app;
 using Mr.BrickAdventures.game.repositories;
 using Mr.BrickAdventures.game.services;
 
@@ -20,10 +21,11 @@ public partial class MainMenu : Control
     [Export] public Label VersionLabel { get; set; } = null!;
     [Export] public Control SettingsControl { get; set; } = null!;
     [Export] public Control CreditsControl { get; set; } = null!;
-    [Export] public PackedScene FirstLevelScene { get; set; } = null!;
 
     [Dependency] public SaveService Save => this.DependOn<SaveService>();
     [Dependency] public LevelRepository Levels => this.DependOn<LevelRepository>();
+    [Dependency] public IGameScenes Scenes => this.DependOn<IGameScenes>();
+    [Dependency] public ILevelCatalog Catalog => this.DependOn<ILevelCatalog>();
 
     public void OnReady() {
         VersionLabel.Text = $"v. {ProjectSettings.GetSetting("application/config/version")}";
@@ -44,15 +46,13 @@ public partial class MainMenu : Control
     private void OnNewGamePressed() {
         Save.NewGame();
         Levels.SetCurrent(0);
-        GetTree().ChangeSceneToPacked(FirstLevelScene);
+        var first = Catalog.First;
+        Scenes.Load(first);
     }
 
     private void OnContinuePressed() {
-        if (!Save.TryLoad()) {
-            // Fallback: start new game
-            OnNewGamePressed();
-            return;
-        }
-        GetTree().ChangeSceneToPacked(FirstLevelScene);
+        if (!Save.TryLoad()) { OnNewGamePressed(); return; }
+        var scene = Catalog.Get(Levels.Current) ?? Catalog.First;
+        Scenes.Load(scene);
     }
 }