refactor(core): 진행 서비스 및 모델 개선

- ProgressService 로직 개선
- GameState 상태 관리 확장
- MonsterCombatStats 속성 추가
- game_text_l10n 번역 추가

lib/src/core/engine/progress_service.dart

@@ -302,6 +302,27 @@ class ProgressService {
         progress: progress,
         potionInventory: resetPotionInventory,
       );
+
+      // 최종 보스 처치 체크
+      if (progress.finalBossState == FinalBossState.fighting) {
+        // 글리치 갓 처치 완료 - 게임 클리어
+        progress = progress.copyWith(
+          finalBossState: FinalBossState.defeated,
+        );
+        nextState = nextState.copyWith(progress: progress);
+
+        // completeAct를 호출하여 게임 완료 처리
+        final actResult = completeAct(nextState);
+        nextState = actResult.state;
+
+        return ProgressTickResult(
+          state: nextState,
+          leveledUp: false,
+          completedQuest: false,
+          completedAct: true,
+          gameComplete: true,
+        );
+      }
     }
 
     // 시장/판매/구매 태스크 완료 시 처리 (원본 Main.pas:631-649)
@@ -494,7 +515,13 @@ class ProgressService {
       return (progress: progress, queue: queue);
     }
 
-    // 3. MonsterTask 실행 (원본 678-684줄)
+    // 3. 최종 보스 전투 체크
+    // finalBossState == fighting이면 Glitch God 스폰
+    if (state.progress.finalBossState == FinalBossState.fighting) {
+      return _startFinalBossFight(state, progress, queue);
+    }
+
+    // 4. MonsterTask 실행 (원본 678-684줄)
     final level = state.traits.level;
 
     // 원본 Main.pas:548-551: 25% 확률로 Quest Monster 사용
@@ -567,6 +594,61 @@ class ProgressService {
     return (progress: progress, queue: queue);
   }
 
+  /// 최종 보스(Glitch God) 전투 시작
+  ///
+  /// Act V 플롯 완료 후 호출되며, 글리치 갓과의 전투를 설정합니다.
+  ({ProgressState progress, QueueState queue}) _startFinalBossFight(
+    GameState state,
+    ProgressState progress,
+    QueueState queue,
+  ) {
+    final level = state.traits.level;
+
+    // 플레이어 전투 스탯 생성
+    final playerCombatStats = CombatStats.fromStats(
+      stats: state.stats,
+      equipment: state.equipment,
+      level: level,
+    );
+
+    // Glitch God 생성 (레벨 100 최종 보스)
+    final glitchGod = MonsterCombatStats.glitchGod();
+
+    // 전투 상태 초기화
+    final combatState = CombatState.start(
+      playerStats: playerCombatStats,
+      monsterStats: glitchGod,
+    );
+
+    // 전투 시간 추정 (보스 전투는 더 길게)
+    final combatCalculator = CombatCalculator(rng: state.rng);
+    final baseDuration = combatCalculator.estimateCombatDurationMs(
+      player: playerCombatStats,
+      monster: glitchGod,
+    );
+    // 최종 보스는 최소 10초, 최대 60초
+    final durationMillis = baseDuration.clamp(10000, 60000);
+
+    final taskResult = pq_logic.startTask(
+      progress,
+      l10n.taskFinalBoss(glitchGod.name),
+      durationMillis,
+    );
+
+    final updatedProgress = taskResult.progress.copyWith(
+      currentTask: TaskInfo(
+        caption: taskResult.caption,
+        type: TaskType.kill,
+        monsterBaseName: 'Glitch God',
+        monsterPart: '*', // 특수 전리품
+        monsterLevel: glitchGod.level,
+      ),
+      currentCombat: combatState,
+    );
+
+    return (progress: updatedProgress, queue: queue);
+  }
+
   /// Advances quest completion, applies reward, and enqueues next quest task.
   GameState completeQuest(GameState state) {
     final result = pq_logic.completeQuest(
@@ -625,28 +707,45 @@ class ProgressService {
   }
 
   /// Advances plot to next act and applies any act-level rewards.
-  /// Returns gameComplete=true if Act V was completed (game ends).
+  /// Returns gameComplete=true if Final Boss was defeated (game ends).
   ({GameState state, bool gameComplete}) completeAct(GameState state) {
-    // Act V 완료 시 (plotStageCount == 6) 게임 클리어
+    // Act V 완료 시 (plotStageCount == 6) → 최종 보스 전투 시작
     // plotStageCount: 1=Prologue, 2=Act I, 3=Act II, 4=Act III, 5=Act IV, 6=Act V
     if (state.progress.plotStageCount >= 6) {
-      // Act V 완료 - 게임 클리어!
-      // 히스토리만 업데이트하고 새 Act는 생성하지 않음
-      final updatedPlotHistory = [
-        ...state.progress.plotHistory.map(
-          (e) => e.isComplete ? e : e.copyWith(isComplete: true),
-        ),
-        const HistoryEntry(caption: '*** THE END ***', isComplete: true),
-      ];
+      // 이미 최종 보스가 처치되었으면 게임 클리어
+      if (state.progress.finalBossState == FinalBossState.defeated) {
+        final updatedPlotHistory = [
+          ...state.progress.plotHistory.map(
+            (e) => e.isComplete ? e : e.copyWith(isComplete: true),
+          ),
+          const HistoryEntry(caption: '*** THE END ***', isComplete: true),
+        ];
 
-      final updatedProgress = state.progress.copyWith(
-        plotHistory: updatedPlotHistory,
-      );
+        final updatedProgress = state.progress.copyWith(
+          plotHistory: updatedPlotHistory,
+        );
 
-      return (
-        state: state.copyWith(progress: updatedProgress),
-        gameComplete: true,
-      );
+        return (
+          state: state.copyWith(progress: updatedProgress),
+          gameComplete: true,
+        );
+      }
+
+      // 최종 보스가 아직 등장하지 않았으면 보스 전투 시작
+      if (state.progress.finalBossState == FinalBossState.notSpawned) {
+        final updatedProgress = state.progress.copyWith(
+          finalBossState: FinalBossState.fighting,
+        );
+
+        // 게임은 아직 끝나지 않음 - 보스 전투 진행
+        return (
+          state: state.copyWith(progress: updatedProgress),
+          gameComplete: false,
+        );
+      }
+
+      // 보스 전투 중이면 계속 진행 (게임 종료 안 함)
+      return (state: state, gameComplete: false);
     }
 
     final actResult = pq_logic.completeAct(state.progress.plotStageCount);