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>

entrypoints/options/__tests__/App.test.tsx

@@ -7,6 +7,7 @@ import {
   getDefaultPageOrder,
   getFeatureByKey,
 } from '@/config/features';
+import { getMessage } from '@/utils/chromeI18n';
 
 // Mock storageUtil
 vi.mock('@/utils/chromeStorage', () => ({
@@ -16,14 +17,6 @@ vi.mock('@/utils/chromeStorage', () => ({
   },
 }));
 
-// Mock i18next
-vi.mock('react-i18next', () => ({
-  useTranslation: () => ({
-    t: (key: string) => key,
-  }),
-  withTranslation: () => (Component: any) => Component,
-}));
-
 describe('Options App', () => {
   beforeEach(() => {
     vi.clearAllMocks();
@@ -47,7 +40,7 @@ describe('Options App', () => {
     for (const key of defaultOrder) {
       const feature = getFeatureByKey(key);
       if (feature) {
-        expect(screen.getByText(feature.labelKey)).toBeInTheDocument();
+        expect(screen.getByText(getMessage(feature.labelKey))).toBeInTheDocument();
       }
     }
   });
@@ -72,7 +65,7 @@ describe('Options App', () => {
     for (const key of defaultVisible) {
       const feature = getFeatureByKey(key);
       if (feature && key !== 'dashboard') {
-        expect(screen.getByText(feature.labelKey)).toBeInTheDocument();
+        expect(screen.getByText(getMessage(feature.labelKey))).toBeInTheDocument();
       }
     }
   });
@@ -97,7 +90,7 @@ describe('Options App', () => {
     for (const key of defaultOrder) {
       const feature = getFeatureByKey(key);
       if (feature) {
-        expect(screen.getByText(feature.labelKey)).toBeInTheDocument();
+        expect(screen.getByText(getMessage(feature.labelKey))).toBeInTheDocument();
       }
     }
   });
@@ -125,7 +118,7 @@ describe('Options App', () => {
     for (const key of defaultOrder) {
       const feature = getFeatureByKey(key);
       if (feature) {
-        expect(screen.getByText(feature.labelKey)).toBeInTheDocument();
+        expect(screen.getByText(getMessage(feature.labelKey))).toBeInTheDocument();
       }
     }
   });