feat(debug): 모바일 레이아웃에 치트 기능 추가

- MobileCarouselLayout에 치트 버튼 추가
- GameSessionController에 치트 활성화 상태 관리 추가
- ProgressLoop/ProgressService에 치트 메서드 추가

lib/src/core/engine/progress_service.dart

@@ -26,6 +26,7 @@ class ProgressTickResult {
     this.completedQuest = false,
     this.completedAct = false,
     this.playerDied = false,
+    this.gameComplete = false,
   });
 
   final GameState state;
@@ -36,8 +37,11 @@ class ProgressTickResult {
   /// 플레이어 사망 여부 (Phase 4)
   final bool playerDied;
 
+  /// 게임 클리어 여부 (Act V 완료)
+  final bool gameComplete;
+
   bool get shouldAutosave =>
-      leveledUp || completedQuest || completedAct || playerDied;
+      leveledUp || completedQuest || completedAct || playerDied || gameComplete;
 }
 
 /// Drives quest/plot/task progression by applying queued actions and rewards.
@@ -155,6 +159,7 @@ class ProgressService {
     var leveledUp = false;
     var questDone = false;
     var actDone = false;
+    var gameComplete = false;
 
     // 스킬 시스템 시간 업데이트 (Phase 3)
     final skillService = SkillService(rng: state.rng);
@@ -400,8 +405,10 @@ class ProgressService {
       // plot 타입이 dequeue 되면 completeAct 실행 (원본 Main.pas 로직)
       if (dq.kind == QueueKind.plot) {
         nextState = nextState.copyWith(progress: progress, queue: queue);
-        nextState = completeAct(nextState);
+        final actResult = completeAct(nextState);
+        nextState = actResult.state;
         actDone = true;
+        gameComplete = actResult.gameComplete;
         progress = nextState.progress;
         queue = nextState.queue;
       }
@@ -422,6 +429,7 @@ class ProgressService {
       leveledUp: leveledUp,
       completedQuest: questDone,
       completedAct: actDone,
+      gameComplete: gameComplete,
     );
   }
 
@@ -617,7 +625,30 @@ class ProgressService {
   }
 
   /// Advances plot to next act and applies any act-level rewards.
-  GameState completeAct(GameState state) {
+  /// Returns gameComplete=true if Act V was completed (game ends).
+  ({GameState state, bool gameComplete}) completeAct(GameState state) {
+    // Act V 완료 시 (plotStageCount == 5) 게임 클리어
+    // plotStageCount: 0=Prologue, 1=Act I, 2=Act II, 3=Act III, 4=Act IV, 5=Act V
+    if (state.progress.plotStageCount >= 5) {
+      // 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),
+      ];
+
+      final updatedProgress = state.progress.copyWith(
+        plotHistory: updatedPlotHistory,
+      );
+
+      return (
+        state: state.copyWith(progress: updatedProgress),
+        gameComplete: true,
+      );
+    }
+
     final actResult = pq_logic.completeAct(state.progress.plotStageCount);
     var nextState = state;
     for (final reward in actResult.rewards) {
@@ -648,7 +679,7 @@ class ProgressService {
       nextState = _startFirstQuest(nextState);
     }
 
-    return _recalculateEncumbrance(nextState);
+    return (state: _recalculateEncumbrance(nextState), gameComplete: false);
   }
 
   /// 첫 퀘스트 시작 (Act I 시작 시)