text: Title: [UX][API Server] Spinner not shown on the stream webpage
  Body: The spinner seems not rendered in the api streaming. Examples:
  
  <img width="992" alt="Image" src="https://github.com/user-attachments/assets/daa7a5ec-3cb2-46f7-bc08-ff481e580e1b" />
  
  <img width="989" alt="Image" src="https://github.com/user-attachments/assets/33e7fede-5ef2-4206-a420-4e5ae472d5b8" />