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/features/game_session_controller_test.dart

@@ -1,58 +1,12 @@
-import 'package:asciineverdie/src/core/engine/game_mutations.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/game_state.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/features/game/game_session_controller.dart';
 import 'package:fake_async/fake_async.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-class FakeSaveManager implements SaveManager {
-  final List<GameState> savedStates = [];
-  (SaveOutcome, GameState?, bool) Function(String?)? onLoad;
-  SaveOutcome saveOutcome = const SaveOutcome.success();
-
-  @override
-  Future<SaveOutcome> saveState(
-    GameState state, {
-    String? fileName,
-    bool cheatsEnabled = false,
-  }) async {
-    savedStates.add(state);
-    return saveOutcome;
-  }
-
-  @override
-  Future<(SaveOutcome, GameState?, bool)> loadState({String? fileName}) async {
-    if (onLoad != null) {
-      return onLoad!(fileName);
-    }
-    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() {
-  const config = PqConfig();
-  final mutations = GameMutations(config);
-  final progressService = ProgressService(
-    config: config,
-    mutations: mutations,
-    rewards: RewardService(mutations, config),
-  );
+  final progressService = MockFactories.createProgressService();
 
   GameSessionController buildController(
     FakeAsync async,