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_session_controller.dart

@@ -5,7 +5,9 @@ import 'package:askiineverdie/src/core/engine/progress_service.dart';
 import 'package:askiineverdie/src/core/engine/resurrection_service.dart';
 import 'package:askiineverdie/src/core/engine/shop_service.dart';
 import 'package:askiineverdie/src/core/model/game_state.dart';
+import 'package:askiineverdie/src/core/model/game_statistics.dart';
 import 'package:askiineverdie/src/core/storage/save_manager.dart';
+import 'package:askiineverdie/src/core/storage/statistics_storage.dart';
 import 'package:flutter/foundation.dart';
 
 enum GameSessionStatus { idle, loading, running, error, dead }
@@ -18,12 +20,15 @@ class GameSessionController extends ChangeNotifier {
     this.autoSaveConfig = const AutoSaveConfig(),
     Duration tickInterval = const Duration(milliseconds: 50),
     DateTime Function()? now,
+    StatisticsStorage? statisticsStorage,
   }) : _tickInterval = tickInterval,
-       _now = now ?? DateTime.now;
+       _now = now ?? DateTime.now,
+       _statisticsStorage = statisticsStorage ?? StatisticsStorage();
 
   final ProgressService progressService;
   final SaveManager saveManager;
   final AutoSaveConfig autoSaveConfig;
+  final StatisticsStorage _statisticsStorage;
 
   final Duration _tickInterval;
   final DateTime Function() _now;
@@ -36,12 +41,26 @@ class GameSessionController extends ChangeNotifier {
   GameState? _state;
   String? _error;
 
+  // 통계 관련 필드
+  SessionStatistics _sessionStats = SessionStatistics.empty();
+  CumulativeStatistics _cumulativeStats = CumulativeStatistics.empty();
+  int _previousLevel = 0;
+  int _previousGold = 0;
+  int _previousMonstersKilled = 0;
+  int _previousQuestsCompleted = 0;
+
   GameSessionStatus get status => _status;
   GameState? get state => _state;
   String? get error => _error;
   bool get isRunning => _status == GameSessionStatus.running;
   bool get cheatsEnabled => _cheatsEnabled;
 
+  /// 현재 세션 통계
+  SessionStatistics get sessionStats => _sessionStats;
+
+  /// 누적 통계
+  CumulativeStatistics get cumulativeStats => _cumulativeStats;
+
   /// 현재 ProgressLoop 인스턴스 (치트 기능용)
   ProgressLoop? get loop => _loop;
 
@@ -62,6 +81,13 @@ class GameSessionController extends ChangeNotifier {
     _status = GameSessionStatus.running;
     _cheatsEnabled = cheatsEnabled;
 
+    // 통계 초기화
+    if (isNewGame) {
+      _sessionStats = SessionStatistics.empty();
+      await _statisticsStorage.recordGameStart();
+    }
+    _initPreviousValues(state);
+
     _loop = ProgressLoop(
       initialState: state,
       progressService: progressService,
@@ -74,6 +100,7 @@ class GameSessionController extends ChangeNotifier {
     );
 
     _subscription = _loop!.stream.listen((next) {
+      _updateStatistics(next);
       _state = next;
       notifyListeners();
     });
@@ -82,6 +109,76 @@ class GameSessionController extends ChangeNotifier {
     notifyListeners();
   }
 
+  /// 이전 값 초기화 (통계 변화 추적용)
+  void _initPreviousValues(GameState state) {
+    _previousLevel = state.traits.level;
+    _previousGold = state.inventory.gold;
+    _previousMonstersKilled = state.progress.monstersKilled;
+    _previousQuestsCompleted = state.progress.questCount;
+  }
+
+  /// 상태 변화에 따른 통계 업데이트
+  void _updateStatistics(GameState next) {
+    // 플레이 시간 업데이트
+    _sessionStats = _sessionStats.updatePlayTime(next.skillSystem.elapsedMs);
+
+    // 레벨업 감지
+    if (next.traits.level > _previousLevel) {
+      final levelUps = next.traits.level - _previousLevel;
+      for (var i = 0; i < levelUps; i++) {
+        _sessionStats = _sessionStats.recordLevelUp();
+      }
+      _previousLevel = next.traits.level;
+
+      // 최고 레벨 업데이트
+      unawaited(_statisticsStorage.updateHighestLevel(next.traits.level));
+    }
+
+    // 골드 변화 감지
+    if (next.inventory.gold > _previousGold) {
+      final earned = next.inventory.gold - _previousGold;
+      _sessionStats = _sessionStats.recordGoldEarned(earned);
+
+      // 최대 골드 업데이트
+      unawaited(_statisticsStorage.updateHighestGold(next.inventory.gold));
+    } else if (next.inventory.gold < _previousGold) {
+      final spent = _previousGold - next.inventory.gold;
+      _sessionStats = _sessionStats.recordGoldSpent(spent);
+    }
+    _previousGold = next.inventory.gold;
+
+    // 몬스터 처치 감지
+    if (next.progress.monstersKilled > _previousMonstersKilled) {
+      final kills = next.progress.monstersKilled - _previousMonstersKilled;
+      for (var i = 0; i < kills; i++) {
+        _sessionStats = _sessionStats.recordKill();
+      }
+      _previousMonstersKilled = next.progress.monstersKilled;
+    }
+
+    // 퀘스트 완료 감지
+    if (next.progress.questCount > _previousQuestsCompleted) {
+      final quests = next.progress.questCount - _previousQuestsCompleted;
+      for (var i = 0; i < quests; i++) {
+        _sessionStats = _sessionStats.recordQuestComplete();
+      }
+      _previousQuestsCompleted = next.progress.questCount;
+    }
+  }
+
+  /// 누적 통계 로드
+  Future<void> loadCumulativeStats() async {
+    _cumulativeStats = await _statisticsStorage.loadCumulative();
+    notifyListeners();
+  }
+
+  /// 세션 통계를 누적 통계에 병합
+  Future<void> mergeSessionStats() async {
+    await _statisticsStorage.mergeSession(_sessionStats);
+    _cumulativeStats = await _statisticsStorage.loadCumulative();
+    notifyListeners();
+  }
+
   Future<void> loadAndStart({
     String? fileName,
     bool cheatsEnabled = false,
@@ -148,6 +245,7 @@ class GameSessionController extends ChangeNotifier {
 
   /// 플레이어 사망 콜백 (ProgressLoop에서 호출)
   void _onPlayerDied() {
+    _sessionStats = _sessionStats.recordDeath();
     _status = GameSessionStatus.dead;
     notifyListeners();
   }