phsl / new-api

- 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.