test: 테스트 파일 추가 및 리팩토링 반영

- combat_calculator_test, skill_service_test, stat_calculator_test 추가
- mock_factories.dart 헬퍼 추가
- progress_loop_test, game_session_controller_test 서비스 분리 반영

test/core/engine/progress_loop_test.dart

@@ -1,63 +1,18 @@
-import 'package:asciineverdie/src/core/engine/game_mutations.dart';
 import 'package:asciineverdie/src/core/engine/progress_loop.dart';
-import 'package:asciineverdie/src/core/engine/progress_service.dart';
-import 'package:asciineverdie/src/core/engine/reward_service.dart';
 import 'package:asciineverdie/src/core/model/combat_state.dart';
 import 'package:asciineverdie/src/core/model/combat_stats.dart';
 import 'package:asciineverdie/src/core/model/game_state.dart';
 import 'package:asciineverdie/src/core/model/monster_combat_stats.dart';
-import 'package:asciineverdie/src/core/model/pq_config.dart';
-import 'package:asciineverdie/src/core/storage/save_manager.dart';
-import 'package:asciineverdie/src/core/storage/save_repository.dart';
-import 'package:asciineverdie/src/core/storage/save_service.dart';
 import 'package:asciineverdie/src/core/util/balance_constants.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-class _FakeSaveManager implements SaveManager {
-  final List<GameState> savedStates = [];
-
-  @override
-  Future<SaveOutcome> saveState(
-    GameState state, {
-    String? fileName,
-    bool cheatsEnabled = false,
-  }) async {
-    savedStates.add(state);
-    return const SaveOutcome.success();
-  }
-
-  @override
-  Future<(SaveOutcome, GameState?, bool)> loadState({String? fileName}) async {
-    return (const SaveOutcome.success(), null, false);
-  }
-
-  @override
-  Future<List<SaveFileInfo>> listSaves() async => [];
-
-  @override
-  Future<SaveOutcome> deleteSave({String? fileName}) async {
-    return const SaveOutcome.success();
-  }
-
-  @override
-  Future<bool> saveExists({String? fileName}) async => false;
-}
+import '../../helpers/mock_factories.dart';
 
 void main() {
-  late ProgressService service;
-
-  setUp(() {
-    const config = PqConfig();
-    final mutations = GameMutations(config);
-    service = ProgressService(
-      config: config,
-      mutations: mutations,
-      rewards: RewardService(mutations, config),
-    );
-  });
+  late final service = MockFactories.createProgressService();
 
   test('autosaves on level-up and stop when configured', () async {
-    final saveManager = _FakeSaveManager();
+    final saveManager = FakeSaveManager();
 
     // 레벨 1에서 레벨업에 필요한 경험치
     final requiredExp = ExpConstants.requiredExp(1);