refactor: 迁移 i18n 系统从 react-i18next 到 chrome.i18n

- 移除 react-i18next、i18next 及相关依赖
- 删除旧的 i18n/ 目录和 useLazyTranslation 工具
- 新增 utils/chromeI18n.ts 类型安全 wrapper（useI18n Hook + getMessage）
- 生成 public/_locales/{zh,en}/messages.json（298 个翻译 key）
- 批量更新 39+ 组件文件的导入和翻译调用
- 转换翻译键格式：namespace:key → namespace_key
- 修复 ErrorBoundary/PageErrorBoundary 从 withTranslation HOC 改为直接调用 getMessage
- 更新 vitest.setup.ts mock 加载实际翻译文本
- 修复 11 个测试文件的断言以匹配中文翻译
- TypeScript、ESLint、547 项测试全部通过

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

config/__tests__/features.test.ts

@@ -50,14 +50,14 @@ describe('features', () => {
       const feature = getFeatureByKey('dashboard');
       expect(feature).toBeDefined();
       expect(feature?.key).toBe('dashboard');
-      expect(feature?.labelKey).toBe('features:dashboard.title');
+      expect(feature?.labelKey).toBe('dashboard_title');
     });
 
     it('should return timestamp feature', () => {
       const feature = getFeatureByKey('timestamp');
       expect(feature).toBeDefined();
       expect(feature?.key).toBe('timestamp');
-      expect(feature?.labelKey).toBe('features:timestamp.title');
+      expect(feature?.labelKey).toBe('timestamp_title');
       expect(feature?.themeColorKey).toBeDefined();
     });
 
@@ -65,7 +65,7 @@ describe('features', () => {
       const feature = getFeatureByKey('storageCleaner');
       expect(feature).toBeDefined();
       expect(feature?.key).toBe('storageCleaner');
-      expect(feature?.labelKey).toBe('features:storageCleaner.title');
+      expect(feature?.labelKey).toBe('storageCleaner_title');
     });
 
     it('should return undefined for invalid key', () => {