feat(audio): 화면들 채널별 SFX API 적용

- game_play_screen: playPlayerSfx/playMonsterSfx 분리 사용
- settings_screen: 오디오 설정 UI 개선

lib/src/features/game/game_play_screen.dart

@@ -129,8 +129,8 @@ class _GamePlayScreenState extends State<GamePlayScreen>
         '${game_l10n.uiLevelUp} Lv.${state.traits.level}',
         CombatLogType.levelUp,
       );
-      // 오디오: 레벨업 SFX
-      widget.audioService?.playSfx('level_up');
+      // 오디오: 레벨업 SFX (플레이어 채널)
+      widget.audioService?.playPlayerSfx('level_up');
       _resetSpecialAnimationAfterFrame();
 
       // Phase 9: Act 변경 감지 (레벨 기반)
@@ -168,8 +168,8 @@ class _GamePlayScreenState extends State<GamePlayScreen>
           CombatLogType.questComplete,
         );
       }
-      // 오디오: 퀘스트 완료 SFX
-      widget.audioService?.playSfx('quest_complete');
+      // 오디오: 퀘스트 완료 SFX (플레이어 채널)
+      widget.audioService?.playPlayerSfx('quest_complete');
       _resetSpecialAnimationAfterFrame();
     }
     _lastQuestCount = state.progress.questCount;
@@ -283,26 +283,33 @@ class _GamePlayScreenState extends State<GamePlayScreen>
     _wasInBattleTask = isInBattleTask;
   }
 
-  /// 전투 이벤트에 따른 SFX 재생
+  /// 전투 이벤트별 SFX 재생 (채널 분리)
+  ///
+  /// 플레이어 이펙트와 몬스터 이펙트를 별도 채널에서 재생하여
+  /// 사운드 충돌을 방지하고 완료를 보장합니다.
   void _playCombatEventSfx(CombatEvent event) {
     final audio = widget.audioService;
     if (audio == null) return;
 
     switch (event.type) {
+      // 플레이어 채널: 플레이어가 발생시키는 이펙트
       case CombatEventType.playerAttack:
-        audio.playSfx('attack');
-      case CombatEventType.monsterAttack:
-        audio.playSfx('hit');
+        audio.playPlayerSfx('attack');
       case CombatEventType.playerSkill:
-        audio.playSfx('skill');
+        audio.playPlayerSfx('skill');
       case CombatEventType.playerHeal:
       case CombatEventType.playerPotion:
-        audio.playSfx('item');
       case CombatEventType.potionDrop:
-        audio.playSfx('item');
+        audio.playPlayerSfx('item');
       case CombatEventType.playerBuff:
       case CombatEventType.playerDebuff:
-        audio.playSfx('skill');
+        audio.playPlayerSfx('skill');
+
+      // 몬스터 채널: 몬스터가 발생시키는 이펙트 (플레이어 피격)
+      case CombatEventType.monsterAttack:
+        audio.playMonsterSfx('hit');
+
+      // SFX 없음
       case CombatEventType.dotTick:
         // DOT 틱은 SFX 없음 (너무 자주 발생)
         break;
@@ -685,6 +692,14 @@ class _GamePlayScreenState extends State<GamePlayScreen>
           );
         }
       },
+      onBgmVolumeChange: (volume) {
+        setState(() => _bgmVolume = volume);
+        widget.audioService?.setBgmVolume(volume);
+      },
+      onSfxVolumeChange: (volume) {
+        setState(() => _sfxVolume = volume);
+        widget.audioService?.setSfxVolume(volume);
+      },
     );
   }
 

lib/src/features/settings/settings_screen.dart

@@ -13,6 +13,8 @@ class SettingsScreen extends StatefulWidget {
     required this.currentThemeMode,
     required this.onThemeModeChange,
     this.onLocaleChange,
+    this.onBgmVolumeChange,
+    this.onSfxVolumeChange,
   });
 
   final SettingsRepository settingsRepository;
@@ -20,6 +22,12 @@ class SettingsScreen extends StatefulWidget {
   final void Function(ThemeMode mode) onThemeModeChange;
   final void Function(String locale)? onLocaleChange;
 
+  /// BGM 볼륨 변경 콜백 (AudioService 연동용)
+  final void Function(double volume)? onBgmVolumeChange;
+
+  /// SFX 볼륨 변경 콜백 (AudioService 연동용)
+  final void Function(double volume)? onSfxVolumeChange;
+
   @override
   State<SettingsScreen> createState() => _SettingsScreenState();
 
@@ -30,6 +38,8 @@ class SettingsScreen extends StatefulWidget {
     required ThemeMode currentThemeMode,
     required void Function(ThemeMode mode) onThemeModeChange,
     void Function(String locale)? onLocaleChange,
+    void Function(double volume)? onBgmVolumeChange,
+    void Function(double volume)? onSfxVolumeChange,
   }) {
     return showModalBottomSheet<void>(
       context: context,
@@ -45,6 +55,8 @@ class SettingsScreen extends StatefulWidget {
           currentThemeMode: currentThemeMode,
           onThemeModeChange: onThemeModeChange,
           onLocaleChange: onLocaleChange,
+          onBgmVolumeChange: onBgmVolumeChange,
+          onSfxVolumeChange: onSfxVolumeChange,
         ),
       ),
     );
@@ -147,6 +159,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
                   onChanged: (value) {
                     setState(() => _bgmVolume = value);
                     widget.settingsRepository.saveBgmVolume(value);
+                    widget.onBgmVolumeChange?.call(value);
                   },
                 ),
                 const SizedBox(height: 8),
@@ -157,6 +170,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
                   onChanged: (value) {
                     setState(() => _sfxVolume = value);
                     widget.settingsRepository.saveSfxVolume(value);
+                    widget.onSfxVolumeChange?.call(value);
                   },
                 ),
                 const SizedBox(height: 24),
@@ -241,7 +255,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
               Icon(
                 icon,
                 color: isSelected
-                    ? theme.colorScheme.primary
+                    ? theme.colorScheme.onPrimaryContainer
                     : theme.colorScheme.onSurface,
               ),
               const SizedBox(height: 4),
@@ -251,7 +265,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
                   fontSize: 12,
                   fontWeight: isSelected ? FontWeight.bold : FontWeight.normal,
                   color: isSelected
-                      ? theme.colorScheme.primary
+                      ? theme.colorScheme.onPrimaryContainer
                       : theme.colorScheme.onSurface,
                 ),
               ),