How to add UI for your RAG?!?

Just built some FastAPI SSE backend streaming LLM responses token-by-token,
after i got some free time.

Two things broke in production that worked fine locally 🙃:

• nginx buffers SSE by default. The stream was delivering locally, dead
  silent on Railway. proxy_buffering off, two hours later, fixed.

• The LLM API returns an empty_retrieval event when no docs match. I wasn't
  handling it, so the frontend sat on a loading spinner indefinitely. Added
  the handler, resolved.

https://zooming-charm-production-547e.up.railway.app/