refactor(core): 진행 루프, 저장 데이터, 저장 관리자 개선

- ProgressLoop 로직 정리
- SaveData 모델 확장
- SaveManager 개선

lib/src/core/model/save_data.dart

@@ -16,9 +16,10 @@ class GameSave {
     required this.skillBook,
     required this.progress,
     required this.queue,
+    this.cheatsEnabled = false,
   });
 
-  factory GameSave.fromState(GameState state) {
+  factory GameSave.fromState(GameState state, {bool cheatsEnabled = false}) {
     return GameSave(
       version: kSaveVersion,
       rngState: state.rng.state,
@@ -29,6 +30,7 @@ class GameSave {
       skillBook: state.skillBook,
       progress: state.progress,
       queue: state.queue,
+      cheatsEnabled: cheatsEnabled,
     );
   }
 
@@ -41,10 +43,12 @@ class GameSave {
   final SkillBook skillBook;
   final ProgressState progress;
   final QueueState queue;
+  final bool cheatsEnabled;
 
   Map<String, dynamic> toJson() {
     return {
       'version': version,
+      'cheatsEnabled': cheatsEnabled,
       'rng': rngState,
       'traits': {
         'name': traits.name,
@@ -144,6 +148,7 @@ class GameSave {
 
     return GameSave(
       version: json['version'] as int? ?? kSaveVersion,
+      cheatsEnabled: json['cheatsEnabled'] as bool? ?? false,
       rngState: json['rng'] as int? ?? 0,
       traits: Traits(
         name: traitsJson['name'] as String? ?? '',