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>

apps/wolf_3d_gui/test/game_screen_lifecycle_audio_test.dart

@@ -1,69 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:wolf_3d_dart/wolf_3d_data_types.dart';
-import 'package:wolf_3d_dart/wolf_3d_engine.dart';
-import 'package:wolf_3d_flutter/wolf_3d_flutter.dart';
-import 'package:wolf_3d_gui/screens/game_screen.dart';
-
-class _CountingAudio implements EngineAudio {
-  @override
-  WolfensteinData? activeGame;
-
-  int stopAllAudioCallCount = 0;
-  int disposeCallCount = 0;
-
-  @override
-  Future<void> debugSoundTest() async {}
-
-  @override
-  Future<void> init() async {}
-
-  @override
-  void playLevelMusic(Music music) {}
-
-  @override
-  void playMenuMusic() {}
-
-  @override
-  void playSoundEffect(SoundEffect effect) {}
-
-  @override
-  void playSoundEffectId(int sfxId) {}
-
-  @override
-  Future<void> stopAllAudio() async {
-    stopAllAudioCallCount++;
-    await Future<void>.delayed(const Duration(milliseconds: 1));
-  }
-
-  @override
-  void stopMusic() {}
-
-  @override
-  void dispose() {
-    disposeCallCount++;
-  }
-}
-
-void main() {
-  testWidgets('dispose path shuts down audio', (tester) async {
-    final audio = _CountingAudio();
-    final wolf3d = Wolf3d(audioBackend: audio);
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: GameScreen(
-          wolf3d: wolf3d,
-          skipEngineBootstrapForTest: true,
-          appExitHandler: () async {},
-        ),
-      ),
-    );
-
-    await tester.pumpWidget(const MaterialApp(home: SizedBox.shrink()));
-    await tester.pump(const Duration(milliseconds: 10));
-
-    expect(audio.stopAllAudioCallCount, 1);
-    expect(audio.disposeCallCount, 1);
-  });
-}