feat: complete internationalization (i18n) for components

Implemented comprehensive i18n translation support for the following components:

1. GitSettings.jsx - Git configuration interface
2. ApiKeysSettings.jsx - API keys settings
3. CredentialsSettings.jsx - Credentials settings (GitHub tokens)
4. TasksSettings.jsx - TaskMaster task management settings
5. ChatInterface.jsx - Chat interface (major translation work)

New translation files:
- src/i18n/locales/en/chat.json - English chat interface translations
- src/i18n/locales/zh-CN/chat.json - Chinese chat interface translations

ChatInterface.jsx translations:
- Code block copy buttons (Copy, Copied, Copy code)
- Message type labels (User, Error, Tool, Claude, Cursor, Codex)
- Tool settings tooltip
- Search result display (pattern, in, results)
- Codex permission modes (Default, Accept Edits, Bypass Permissions, Plan)
- Input placeholder and hint text
- Keyboard shortcut hints (Ctrl+Enter/Enter modes)
- Command menu button

i18n configuration updates:
- Registered chat namespace in config.js
- Extended settings.json translations (git, apiKeys, tasks, agents, mcpServers sections)

完成以下组件的 i18n 翻译工作：

1. GitSettings.jsx - Git 配置界面
2. ApiKeysSettings.jsx - API 密钥设置
3. CredentialsSettings.jsx - 凭据设置（GitHub Token）
4. TasksSettings.jsx - TaskMaster 任务管理设置
5. ChatInterface.jsx - 聊天界面（主要翻译工作）

新增翻译文件：
- src/i18n/locales/en/chat.json - 英文聊天界面翻译
- src/i18n/locales/zh-CN/chat.json - 中文聊天界面翻译

ChatInterface.jsx 翻译内容：
- 代码块复制按钮
- 消息类型标签
- 工具设置提示
- 搜索结果显示
- Codex 权限模式（默认、编辑、无限制、计划模式）
- 输入框占位符和提示文本
- 键盘快捷键提示
- 命令菜单按钮

更新 i18n 配置：
- 在 config.js 中注册 chat 命名空间
- 扩展 settings.json 翻译（git、apiKeys、tasks、agents、mcpServers 等部分）

src/components/settings/AccountContent.jsx

@@ -4,6 +4,7 @@ import { LogIn } from 'lucide-react';
 import ClaudeLogo from '../ClaudeLogo';
 import CursorLogo from '../CursorLogo';
 import CodexLogo from '../CodexLogo';
+import { useTranslation } from 'react-i18next';
 
 const agentConfig = {
   claude: {
@@ -39,6 +40,7 @@ const agentConfig = {
 };
 
 export default function AccountContent({ agent, authStatus, onLogin }) {
+  const { t } = useTranslation('settings');
   const config = agentConfig[agent];
   const { Logo } = config;
 
@@ -47,8 +49,8 @@ export default function AccountContent({ agent, authStatus, onLogin }) {
       <div className="flex items-center gap-3 mb-4">
         <Logo className="w-6 h-6" />
         <div>
-          <h3 className="text-lg font-medium text-foreground">{config.name} Account</h3>
-          <p className="text-sm text-muted-foreground">{config.description}</p>
+          <h3 className="text-lg font-medium text-foreground">{config.name}</h3>
+          <p className="text-sm text-muted-foreground">{t(`agents.account.${agent}.description`)}</p>
         </div>
       </div>
 
@@ -58,30 +60,30 @@ export default function AccountContent({ agent, authStatus, onLogin }) {
           <div className="flex items-center gap-3">
             <div className="flex-1">
               <div className={`font-medium ${config.textClass}`}>
-                Connection Status
+                {t('agents.connectionStatus')}
               </div>
               <div className={`text-sm ${config.subtextClass}`}>
                 {authStatus?.loading ? (
-                  'Checking authentication status...'
+                  t('agents.authStatus.checkingAuth')
                 ) : authStatus?.authenticated ? (
-                  `Logged in as ${authStatus.email || 'authenticated user'}`
+                  t('agents.authStatus.loggedInAs', { email: authStatus.email || t('agents.authStatus.authenticatedUser') })
                 ) : (
-                  'Not connected'
+                  t('agents.authStatus.notConnected')
                 )}
               </div>
             </div>
             <div>
               {authStatus?.loading ? (
                 <Badge variant="secondary" className="bg-gray-100 dark:bg-gray-800">
-                  Checking...
+                  {t('agents.authStatus.checking')}
                 </Badge>
               ) : authStatus?.authenticated ? (
                 <Badge variant="success" className="bg-green-100 text-green-800 dark:bg-green-900/30 dark:text-green-300">
-                  Connected
+                  {t('agents.authStatus.connected')}
                 </Badge>
               ) : (
                 <Badge variant="secondary" className="bg-gray-100 text-gray-800 dark:bg-gray-800 dark:text-gray-300">
-                  Disconnected
+                  {t('agents.authStatus.disconnected')}
                 </Badge>
               )}
             </div>
@@ -91,12 +93,12 @@ export default function AccountContent({ agent, authStatus, onLogin }) {
             <div className="flex items-center justify-between">
               <div>
                 <div className={`font-medium ${config.textClass}`}>
-                  {authStatus?.authenticated ? 'Re-authenticate' : 'Login'}
+                  {authStatus?.authenticated ? t('agents.login.reAuthenticate') : t('agents.login.title')}
                 </div>
                 <div className={`text-sm ${config.subtextClass}`}>
                   {authStatus?.authenticated
-                    ? 'Sign in with a different account or refresh credentials'
-                    : `Sign in to your ${config.name} account to enable AI features`}
+                    ? t('agents.login.reAuthDescription')
+                    : t('agents.login.description', { agent: config.name })}
                 </div>
               </div>
               <Button
@@ -105,7 +107,7 @@ export default function AccountContent({ agent, authStatus, onLogin }) {
                 size="sm"
               >
                 <LogIn className="w-4 h-4 mr-2" />
-                {authStatus?.authenticated ? 'Re-login' : 'Login'}
+                {authStatus?.authenticated ? t('agents.login.reLoginButton') : t('agents.login.button')}
               </Button>
             </div>
           </div>
@@ -113,7 +115,7 @@ export default function AccountContent({ agent, authStatus, onLogin }) {
           {authStatus?.error && (
             <div className="border-t border-gray-200 dark:border-gray-700 pt-4">
               <div className="text-sm text-red-600 dark:text-red-400">
-                Error: {authStatus.error}
+                {t('agents.error', { error: authStatus.error })}
               </div>
             </div>
           )}