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/lib/main.dart

@@ -8,96 +8,20 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:window_manager/window_manager.dart';
 import 'package:wolf_3d_flutter/wolf_3d_flutter.dart';
-import 'package:wolf_3d_gui/screens/game_screen.dart';
 
 /// Creates the application shell after loading available Wolf3D data sets.
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
 
-  if (_supportsDesktopWindowing) {
+  if (supportsDesktopWindowing) {
     await windowManager.ensureInitialized();
   }
 
-  final Wolf3d wolf3d = await Wolf3d().init();
+  final Wolf3d wolf3d = await Wolf3d().init(debug: kDebugMode);
 
   runApp(
     MaterialApp(
-      darkTheme: ThemeData.dark(useMaterial3: true),
-      theme: ThemeData.light(useMaterial3: true),
-      themeMode: ThemeMode.system,
-      home: wolf3d.availableGames.isEmpty
-          ? const _NoGameDataScreen()
-          : GameScreen(wolf3d: wolf3d),
+      home: Wolf3dApp(wolf3d: wolf3d),
     ),
   );
 }
-
-/// Whether desktop window-management APIs should be initialized for this host.
-bool get _supportsDesktopWindowing {
-  if (kIsWeb) {
-    return false;
-  }
-
-  return switch (defaultTargetPlatform) {
-    TargetPlatform.linux ||
-    TargetPlatform.windows ||
-    TargetPlatform.macOS => true,
-    _ => false,
-  };
-}
-
-class _NoGameDataScreen extends StatelessWidget {
-  const _NoGameDataScreen();
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-      backgroundColor: const Color(0xFF140000),
-      body: Center(
-        child: Padding(
-          padding: const EdgeInsets.all(24),
-          child: ConstrainedBox(
-            constraints: const BoxConstraints(maxWidth: 640),
-            child: DecoratedBox(
-              decoration: BoxDecoration(
-                color: const Color(0xFF590002),
-                border: Border.all(color: const Color(0xFFB00000), width: 2),
-              ),
-              child: const Padding(
-                padding: EdgeInsets.all(20),
-                child: Column(
-                  mainAxisSize: MainAxisSize.min,
-                  crossAxisAlignment: CrossAxisAlignment.start,
-                  children: [
-                    Text(
-                      'WOLF3D DATA NOT FOUND',
-                      style: TextStyle(
-                        color: Color(0xFFFFF700),
-                        fontSize: 24,
-                        fontWeight: FontWeight.bold,
-                      ),
-                    ),
-                    SizedBox(height: 16),
-                    Text(
-                      'No game files were discovered.\n\n'
-                      'Add Wolfenstein 3D data files to one of these locations:\n'
-                      '- packages/wolf_3d_assets/assets/retail\n'
-                      '- packages/wolf_3d_assets/assets/shareware\n'
-                      '- or a discoverable local game-data folder.\n\n'
-                      'Restart the app after adding the files.',
-                      style: TextStyle(
-                        color: Colors.white,
-                        fontSize: 15,
-                        height: 1.4,
-                      ),
-                    ),
-                  ],
-                ),
-              ),
-            ),
-          ),
-        ),
-      ),
-    );
-  }
-}