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/i18n/config.js

@@ -18,11 +18,13 @@ import enCommon from './locales/en/common.json';
 import enSettings from './locales/en/settings.json';
 import enAuth from './locales/en/auth.json';
 import enSidebar from './locales/en/sidebar.json';
+import enChat from './locales/en/chat.json';
 
 import zhCommon from './locales/zh-CN/common.json';
 import zhSettings from './locales/zh-CN/settings.json';
 import zhAuth from './locales/zh-CN/auth.json';
 import zhSidebar from './locales/zh-CN/sidebar.json';
+import zhChat from './locales/zh-CN/chat.json';
 
 // Import supported languages configuration
 import { languages } from './languages.js';
@@ -53,12 +55,14 @@ i18n
         settings: enSettings,
         auth: enAuth,
         sidebar: enSidebar,
+        chat: enChat,
       },
       'zh-CN': {
         common: zhCommon,
         settings: zhSettings,
         auth: zhAuth,
         sidebar: zhSidebar,
+        chat: zhChat,
       },
     },
 
@@ -72,7 +76,7 @@ i18n
     debug: import.meta.env.DEV,
 
     // Namespaces - load only what's needed
-    ns: ['common', 'settings', 'auth', 'sidebar'],
+    ns: ['common', 'settings', 'auth', 'sidebar', 'chat'],
     defaultNS: 'common',
 
     // Key separator for nested keys (default: '.')