feat(ui): 도움말 다이얼로그 및 UI 개선

- HelpDialog 추가
- 게임 화면에 통계/도움말 버튼 추가
- CombatLog에 디버프 이벤트 표시
- AudioService mp3 확장자 지원
- 설정 텍스트 l10n 추가

lib/src/features/game/game_play_screen.dart

@@ -32,7 +32,10 @@ import 'package:askiineverdie/src/features/game/widgets/task_progress_panel.dart
 import 'package:askiineverdie/src/features/game/widgets/active_buff_panel.dart';
 import 'package:askiineverdie/src/features/game/layouts/mobile_carousel_layout.dart';
 import 'package:askiineverdie/src/features/settings/settings_screen.dart';
+import 'package:askiineverdie/src/features/game/widgets/statistics_dialog.dart';
+import 'package:askiineverdie/src/features/game/widgets/help_dialog.dart';
 import 'package:askiineverdie/src/core/storage/settings_repository.dart';
+import 'package:askiineverdie/src/core/audio/audio_service.dart';
 
 /// 게임 진행 화면 (Main.dfm 기반 3패널 레이아웃)
 ///
@@ -41,6 +44,7 @@ class GamePlayScreen extends StatefulWidget {
   const GamePlayScreen({
     super.key,
     required this.controller,
+    this.audioService,
     this.forceCarouselLayout = false,
     this.forceDesktopLayout = false,
     this.onThemeModeChange,
@@ -49,6 +53,9 @@ class GamePlayScreen extends StatefulWidget {
 
   final GameSessionController controller;
 
+  /// 오디오 서비스 (BGM/SFX 재생)
+  final AudioService? audioService;
+
   /// 테스트 모드: 웹에서도 모바일 캐로셀 레이아웃 강제 사용
   final bool forceCarouselLayout;
 
@@ -89,6 +96,13 @@ class _GamePlayScreenState extends State<GamePlayScreen>
   // 전투 이벤트 추적 (마지막 처리된 이벤트 수)
   int _lastProcessedEventCount = 0;
 
+  // 오디오 상태 추적
+  bool _wasInCombat = false;
+
+  // 사운드 볼륨 상태 (모바일 설정 UI용)
+  double _bgmVolume = 0.7;
+  double _sfxVolume = 0.8;
+
   void _checkSpecialEvents(GameState state) {
     // Phase 8: 태스크 변경 시 로그 추가
     final currentCaption = state.progress.currentTask.caption;
@@ -102,6 +116,9 @@ class _GamePlayScreenState extends State<GamePlayScreen>
     // 전투 이벤트 처리 (Combat Events)
     _processCombatEvents(state);
 
+    // 오디오: 전투 상태 변경 시 BGM 전환
+    _updateBgmForCombatState(state);
+
     // 레벨업 감지
     if (state.traits.level > _lastLevel && _lastLevel > 0) {
       _specialAnimation = AsciiAnimationType.levelUp;
@@ -110,6 +127,8 @@ class _GamePlayScreenState extends State<GamePlayScreen>
         '${game_l10n.uiLevelUp} Lv.${state.traits.level}',
         CombatLogType.levelUp,
       );
+      // 오디오: 레벨업 SFX
+      widget.audioService?.playSfx('level_up');
       _resetSpecialAnimationAfterFrame();
 
       // Phase 9: Act 변경 감지 (레벨 기반)
@@ -147,6 +166,8 @@ class _GamePlayScreenState extends State<GamePlayScreen>
           CombatLogType.questComplete,
         );
       }
+      // 오디오: 퀘스트 완료 SFX
+      widget.audioService?.playSfx('quest_complete');
       _resetSpecialAnimationAfterFrame();
     }
     _lastQuestCount = state.progress.questCount;
@@ -192,11 +213,74 @@ class _GamePlayScreenState extends State<GamePlayScreen>
     for (final event in newEvents) {
       final (message, type) = _formatCombatEvent(event);
       _addCombatLog(message, type);
+
+      // 오디오: 전투 이벤트에 따른 SFX 재생
+      _playCombatEventSfx(event);
     }
 
     _lastProcessedEventCount = events.length;
   }
 
+  /// 전투 상태에 따른 BGM 전환
+  void _updateBgmForCombatState(GameState state) {
+    final audio = widget.audioService;
+    if (audio == null) return;
+
+    final combat = state.progress.currentCombat;
+    final isInCombat = combat != null && combat.isActive;
+
+    if (isInCombat && !_wasInCombat) {
+      // 전투 시작: 보스 여부에 따라 BGM 선택
+      // 몬스터 레벨이 플레이어보다 5 이상 높으면 보스로 간주
+      final monsterLevel = state.progress.currentTask.monsterLevel ?? 0;
+      final playerLevel = state.traits.level;
+      final isBoss = monsterLevel >= playerLevel + 5;
+
+      if (isBoss) {
+        audio.playBgm('boss');
+      } else {
+        audio.playBgm('battle');
+      }
+    } else if (!isInCombat && _wasInCombat) {
+      // 전투 종료: 마을 BGM으로 복귀
+      audio.playBgm('town');
+    }
+
+    _wasInCombat = isInCombat;
+  }
+
+  /// 전투 이벤트에 따른 SFX 재생
+  void _playCombatEventSfx(CombatEvent event) {
+    final audio = widget.audioService;
+    if (audio == null) return;
+
+    switch (event.type) {
+      case CombatEventType.playerAttack:
+        audio.playSfx('attack');
+      case CombatEventType.monsterAttack:
+        audio.playSfx('hit');
+      case CombatEventType.playerSkill:
+        audio.playSfx('skill');
+      case CombatEventType.playerHeal:
+      case CombatEventType.playerPotion:
+        audio.playSfx('item');
+      case CombatEventType.potionDrop:
+        audio.playSfx('item');
+      case CombatEventType.playerBuff:
+      case CombatEventType.playerDebuff:
+        audio.playSfx('skill');
+      case CombatEventType.dotTick:
+        // DOT 틱은 SFX 없음 (너무 자주 발생)
+        break;
+      case CombatEventType.playerEvade:
+      case CombatEventType.monsterEvade:
+      case CombatEventType.playerBlock:
+      case CombatEventType.playerParry:
+        // 회피/방어는 별도 SFX 없음
+        break;
+    }
+  }
+
   /// 전투 이벤트를 메시지와 타입으로 변환
   (String, CombatLogType) _formatCombatEvent(CombatEvent event) {
     final target = event.targetName ?? '';
@@ -256,6 +340,10 @@ class _GamePlayScreenState extends State<GamePlayScreen>
         game_l10n.combatBuffActivated(skillName),
         CombatLogType.buff,
       ),
+      CombatEventType.playerDebuff => (
+        game_l10n.combatDebuffApplied(skillName, target),
+        CombatLogType.debuff,
+      ),
       CombatEventType.dotTick => (
         game_l10n.combatDotTick(skillName, event.damage),
         CombatLogType.dotTick,
@@ -361,6 +449,29 @@ class _GamePlayScreenState extends State<GamePlayScreen>
       _lastQuestCount = state.progress.questCount;
       _lastPlotStageCount = state.progress.plotStageCount;
       _lastAct = getActForLevel(state.traits.level);
+
+      // 초기 전투 상태 확인
+      final combat = state.progress.currentCombat;
+      _wasInCombat = combat != null && combat.isActive;
+    }
+
+    // 누적 통계 로드
+    widget.controller.loadCumulativeStats();
+
+    // 초기 BGM 재생 (마을 테마)
+    widget.audioService?.playBgm('town');
+
+    // 오디오 볼륨 초기화
+    _initAudioVolumes();
+  }
+
+  /// 오디오 볼륨 초기화 (설정에서 로드)
+  Future<void> _initAudioVolumes() async {
+    final audio = widget.audioService;
+    if (audio != null) {
+      _bgmVolume = audio.bgmVolume;
+      _sfxVolume = audio.sfxVolume;
+      if (mounted) setState(() {});
     }
   }
 
@@ -465,6 +576,15 @@ class _GamePlayScreenState extends State<GamePlayScreen>
     return platform == TargetPlatform.iOS || platform == TargetPlatform.android;
   }
 
+  /// 통계 다이얼로그 표시
+  void _showStatisticsDialog(BuildContext context) {
+    StatisticsDialog.show(
+      context,
+      session: widget.controller.sessionStats,
+      cumulative: widget.controller.cumulativeStats,
+    );
+  }
+
   /// 설정 화면 표시
   void _showSettingsScreen(BuildContext context) {
     final settingsRepo = SettingsRepository();
@@ -614,6 +734,17 @@ class _GamePlayScreenState extends State<GamePlayScreen>
                 },
                 currentThemeMode: widget.currentThemeMode,
                 onThemeModeChange: widget.onThemeModeChange,
+                // 사운드 설정
+                bgmVolume: _bgmVolume,
+                sfxVolume: _sfxVolume,
+                onBgmVolumeChange: (volume) {
+                  setState(() => _bgmVolume = volume);
+                  widget.audioService?.setBgmVolume(volume);
+                },
+                onSfxVolumeChange: (volume) {
+                  setState(() => _sfxVolume = volume);
+                  widget.audioService?.setSfxVolume(volume);
+                },
               ),
               // 사망 오버레이
               if (state.isDead && state.deathInfo != null)
@@ -666,6 +797,18 @@ class _GamePlayScreenState extends State<GamePlayScreen>
                   onPressed: () => widget.controller.loop?.cheatCompletePlot(),
                 ),
               ],
+              // 통계 버튼
+              IconButton(
+                icon: const Icon(Icons.bar_chart),
+                tooltip: game_l10n.uiStatistics,
+                onPressed: () => _showStatisticsDialog(context),
+              ),
+              // 도움말 버튼
+              IconButton(
+                icon: const Icon(Icons.help_outline),
+                tooltip: game_l10n.uiHelp,
+                onPressed: () => HelpDialog.show(context),
+              ),
               // 설정 버튼
               IconButton(
                 icon: const Icon(Icons.settings),