feat: Add tests for Wolf3dGuiApp and refactor game data picker management

- Introduced unit tests for the Wolf3dGuiApp to ensure proper directory configuration and audio management.
- Refactored the GameDataPickerManager to streamline directory and file selection processes.
- Removed obsolete GameDataPickerManager and Wolf3dAppManager classes to simplify the architecture.
- Enhanced the Wolf3dFlutterEngine to improve game version handling during save loading.
- Updated existing tests to reflect changes in the game data management structure.
- Removed unnecessary dependencies and cleaned up the codebase for better maintainability.

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

packages/wolf_3d_dart/lib/src/engine/wolf_3d_engine_base.dart

@@ -330,17 +330,21 @@ class WolfEngine {
       final SaveGameFile file = saveGameCodec.decode(bytes);
       GameSessionSnapshot snapshot = file.snapshot;
 
-      int gameIndex = snapshot.currentGameIndex;
-      if (gameIndex < 0 || gameIndex >= _availableGames.length) {
+      int gameIndex = _availableGames.indexWhere(
+        (game) =>
+            game.version == file.gameVersion &&
+            game.dataVersion.name == file.dataVersionName,
+      );
+      if (gameIndex < 0) {
         gameIndex = _availableGames.indexWhere(
-          (game) =>
-              game.version == file.gameVersion &&
-              game.dataVersion.name == file.dataVersionName,
+          (game) => game.version == file.gameVersion,
         );
-        if (gameIndex < 0) {
-          gameIndex = _availableGames.indexWhere(
-            (game) => game.version == file.gameVersion,
-          );
+      }
+      if (gameIndex < 0) {
+        final int snapshotGameIndex = snapshot.currentGameIndex;
+        if (snapshotGameIndex >= 0 &&
+            snapshotGameIndex < _availableGames.length) {
+          gameIndex = snapshotGameIndex;
         }
       }