feat(app): 오디오 및 설정 시스템 통합

- AudioService 앱 수준 초기화 및 dispose
- 게임 화면에서 오디오/설정 연동

lib/src/app.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 
 import 'package:askiineverdie/data/game_text_l10n.dart' as game_l10n;
 import 'package:askiineverdie/l10n/app_localizations.dart';
+import 'package:askiineverdie/src/core/audio/audio_service.dart';
 import 'package:askiineverdie/src/core/engine/game_mutations.dart';
 import 'package:askiineverdie/src/core/engine/progress_service.dart';
 import 'package:askiineverdie/src/core/engine/reward_service.dart';
@@ -30,6 +31,7 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
   late final GameSessionController _controller;
   late final NotificationService _notificationService;
   late final SettingsRepository _settingsRepository;
+  late final AudioService _audioService;
   bool _isCheckingSave = true;
   bool _hasSave = false;
   ThemeMode _themeMode = ThemeMode.system;
@@ -51,9 +53,11 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
     );
     _notificationService = NotificationService();
     _settingsRepository = SettingsRepository();
+    _audioService = AudioService(settingsRepository: _settingsRepository);
 
-    // 초기 설정 로드
+    // 초기 설정 및 오디오 서비스 로드
     _loadSettings();
+    _audioService.init();
     // 세이브 파일 존재 여부 확인
     _checkForExistingSave();
   }
@@ -87,6 +91,7 @@ class _AskiiNeverDieAppState extends State<AskiiNeverDieApp> {
   void dispose() {
     _controller.dispose();
     _notificationService.dispose();
+    _audioService.dispose();
     super.dispose();
   }