refactor(theme): 重构主题相关文件目录结构

- 将主题相关代码目录由 themes 改为 theme
- 更新了对应文件的导入路径
- 调整 logger 导入路径以匹配目录变更
- 修改 main.dart 和 settings_controller.dart 中的主题导入路径
- 优化项目结构，提升代码维护性

lib/core/themes/theme_service.dart → lib/core/theme/theme_service.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:get/get.dart';
 import 'package:get_storage/get_storage.dart';
-import '../../core/utils/logger.dart';
+import '../utils/logger.dart';
 
 class ThemeService {
   final _box = GetStorage();

lib/main.dart

@@ -15,8 +15,8 @@ import 'core/utils/app_lifecycle_manager.dart';
 import 'routes/app_pages.dart';
 import 'routes/app_routes.dart';
 import 'core/translations/app_translations.dart';
-import 'core/themes/app_theme.dart';
+import 'core/theme/app_theme.dart';
-import 'core/themes/theme_service.dart';
+import 'core/theme/theme_service.dart';
 import 'core/bindings/initial_binding.dart';
 import 'core/utils/logger.dart';
 import 'core/services/native_localization_sync.dart';

lib/modules/settings/controllers/settings_controller.dart

@@ -7,7 +7,7 @@ import 'package:get_storage/get_storage.dart';
 import 'package:logger/logger.dart';
 import 'package:package_info_plus/package_info_plus.dart';
 
-import '../../../core/themes/theme_service.dart';
+import '../../../core/theme/theme_service.dart';
 import '../../../core/services/native_localization_sync.dart';
 import '../../../core/translations/app_translations.dart';
 import '../../../data/services/network/dio_manager.dart';