feat: i18n 中英双语界面 — i18next + react-i18next

- 安装 i18next / react-i18next / i18next-browser-languagedetector
- 新建 src/i18n.ts 配置（fallback zh）
- 中/英翻译文件各 ~50 条目
- App.tsx 新增 EN/中 语言切换按钮
- ExportPanel + QrPreview + ModePanel + HistoryList + ErrorBoundary
- 全部 7 种模式组件均支持双语
- 12 前端测试通过，tsc 零错误

gui/src-frontend/src/components/HistoryList.tsx

@@ -1,8 +1,20 @@
+import { useTranslation } from 'react-i18next';
 import { useQrState } from '../store/qrContext';
-import { MODE_LABELS, type HistoryEntry } from '../types';
+import { type HistoryEntry } from '../types';
 import { persistHistory } from '../hooks/useQrEncode';
 
+const MODE_I18N: Record<string, string> = {
+  text: 'mode.text',
+  url: 'mode.url',
+  wifi: 'mode.wifi',
+  vcard: 'mode.vcard',
+  email: 'mode.email',
+  phone: 'mode.phone',
+  sms: 'mode.sms',
+};
+
 export default function HistoryList() {
+  const { t } = useTranslation();
   const { state, dispatch } = useQrState();
 
   const handleClick = (entry: HistoryEntry) => {
@@ -36,21 +48,21 @@ export default function HistoryList() {
     <div className="flex flex-col h-full">
       <div className="flex items-center justify-between mb-2">
         <span className="text-xs font-semibold text-gray-400 uppercase tracking-wider">
-          📋 历史记录
+          📋 {t('history.title')}
         </span>
         {state.history.length > 0 && (
           <button
             onClick={handleClear}
             className="text-xs text-red-400 hover:text-red-600 transition-colors"
           >
-            清空
+            {t('history.clear')}
           </button>
         )}
       </div>
 
       <div className="flex-1 overflow-y-auto space-y-1">
         {state.history.length === 0 && (
-          <p className="text-xs text-gray-400 text-center py-4">暂无记录</p>
+          <p className="text-xs text-gray-400 text-center py-4">{t('history.empty')}</p>
         )}
         {state.history.map((entry) => (
           <div
@@ -61,7 +73,7 @@ export default function HistoryList() {
             <div className="flex-1 min-w-0">
               <div className="flex items-center gap-1.5">
                 <span className="px-1 py-0.5 rounded text-[10px] font-medium bg-blue-100 dark:bg-blue-900/30 text-blue-600 dark:text-blue-400">
-                  {MODE_LABELS[entry.mode] || entry.mode}
+                  {t(MODE_I18N[entry.mode] || entry.mode)}
                 </span>
                 <span className="text-gray-400">{formatTime(entry.timestamp)}</span>
               </div>