🎨feat(ui): Improve Chat page UI and add i18n support

- Replace Banner with full-screen Spin component for better loading UX
- Add English translation for "正在跳转..." ("Redirecting...")
- Integrate i18next translation hook in Chat page component
- Remove unused useEffect import for cleaner code

The Chat page now shows a centered full-screen loading spinner instead of
a banner when redirecting, providing a more consistent and professional
user experience. The loading text is now properly internationalized and
will display "Redirecting..." in English and "正在跳转..." in Chinese.

web/src/i18n/locales/en.json

@@ -1536,6 +1536,7 @@
   "关闭公告": "Close Notice",
   "搜索条件": "Search Conditions",
   "加载中...": "Loading...",
+  "正在跳转...": "Redirecting...",
   "暂无公告": "No Notice",
   "操练场": "Playground",
   "欢迎使用，请完成以下设置以开始使用系统": "Welcome to use, please complete the following settings to start using the system",