Delegate all audio management to the new audio package, then manage that through a new wolf3d class

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

lib/wolf_3d.dart

@@ -2,6 +2,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:wolf_3d_data/wolf_3d_data.dart';
 import 'package:wolf_3d_data_types/wolf_3d_data_types.dart';
+import 'package:wolf_3d_synth/wolf_3d_synth.dart';
 
 class Wolf3d {
   Wolf3d._();
@@ -12,6 +13,9 @@ class Wolf3d {
   final List<WolfensteinData> availableGames = [];
   WolfensteinData? _activeGame;
 
+  // --- Core Systems ---
+  final WolfAudio audio = WolfAudio();
+
   // --- Getters ---
   WolfensteinData get activeGame {
     if (_activeGame == null) {
@@ -20,6 +24,15 @@ class Wolf3d {
     return _activeGame!;
   }
 
+  // --- Episode ---
+  int _activeEpisode = 0;
+
+  int get activeEpisode => _activeEpisode;
+
+  void setActiveEpisode(int episodeIndex) {
+    _activeEpisode = episodeIndex;
+  }
+
   // Convenience getters for the active game's assets
   List<WolfLevel> get levels => activeGame.levels;
   List<Sprite> get walls => activeGame.walls;
@@ -36,6 +49,7 @@ class Wolf3d {
 
   /// Initializes the engine by loading available game data.
   Future<void> init({String? directory}) async {
+    await audio.init();
     availableGames.clear();
 
     // 1. Bundle asset loading (migrated from GameSelectScreen)