Moved all widgets and logic from gui app to Flutter package

- Implemented DebugToolsScreen for navigation to asset galleries.
- Created GameScreen to manage gameplay and renderer integrations.
- Added NoGameDataScreen to handle scenarios with missing game data.
- Developed SpriteGallery for visual browsing of sprite assets.
- Introduced VgaGallery for displaying VGA images from game data.
- Added GalleryGameSelector widget for selecting game variants in galleries.
- Created Wolf3dApp as the main application shell for managing game states.
- Implemented WolfMenuShell for consistent menu layouts across screens.
- Enhanced Wolf3d class to support debug mode and related functionalities.
- Updated pubspec.yaml to include window_manager dependency.
- Added tests for game screen lifecycle and debug mode functionalities.

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_flutter/lib/wolf_3d_flutter.dart

@@ -12,6 +12,30 @@ import 'package:wolf_3d_flutter/wolf_3d_input_flutter.dart';
 export 'package:wolf_3d_dart/wolf_3d_audio.dart' show DebugMusicPlayer;
 
 export 'audio/wolf3d_platform_audio.dart' show Wolf3dPlatformAudio;
+export 'managers/desktop_windowing_support.dart' show supportsDesktopWindowing;
+export 'managers/game_app_lifecycle_manager.dart' show GameAppLifecycleManager;
+export 'managers/game_display_manager.dart' show GameDisplayManager;
+export 'managers/game_persistence_manager.dart' show GamePersistenceManager;
+export 'managers/game_renderer_mode_manager.dart'
+    show GameRendererMode, gameRendererModeFromSettings, handleGlslUnavailable;
+export 'managers/game_screen_input_manager.dart'
+    show
+        HostShortcutBinding,
+        HostShortcutHandler,
+        HostShortcutIntent,
+        HostShortcutRegistry,
+        GameScreenInputManager,
+        isAltEnterShortcut;
+export 'screens/audio_gallery.dart' show AudioGallery;
+export 'screens/debug_tools_screen.dart' show DebugToolsScreen;
+export 'screens/game_screen.dart' show GameScreen;
+export 'screens/no_game_data_screen.dart' show NoGameDataScreen;
+export 'screens/sprite_gallery.dart' show SpriteGallery;
+export 'screens/vga_gallery.dart' show VgaGallery;
+export 'widgets/gallery_game_selector.dart'
+    show GalleryGameSelector, formatGalleryGameTitle;
+export 'widgets/wolf3d_app.dart' show Wolf3dApp;
+export 'widgets/wolf_menu_shell.dart' show WolfMenuShell;
 
 /// Coordinates asset discovery, audio initialization, and input reuse for apps.
 class Wolf3d {
@@ -37,6 +61,17 @@ class Wolf3d {
   /// Shared Flutter input adapter reused by gameplay screens.
   final Wolf3dFlutterInput input = Wolf3dFlutterInput();
 
+  bool _debugEnabled = false;
+
+  /// Whether host-level debug affordances should be visible.
+  bool get isDebugEnabled => _debugEnabled;
+
+  /// Enables host-level debug affordances such as debug navigation UI.
+  Wolf3d enableDebug() {
+    _debugEnabled = true;
+    return this;
+  }
+
   /// The currently selected game data set.
   ///
   /// Throws a [StateError] until [setActiveGame] has been called.
@@ -194,7 +229,12 @@ class Wolf3d {
   }
 
   /// Initializes the engine by loading available game data.
-  Future<Wolf3d> init({String? directory}) async {
+  ///
+  /// Set [debug] to `true` to explicitly enable host-level debug affordances.
+  Future<Wolf3d> init({String? directory, bool debug = false}) async {
+    if (debug) {
+      _debugEnabled = true;
+    }
     await audio.init();
     availableGames.clear();