Root cause: when SSE delivered any chunk, maxAttempts was set to 1 with
no delay. That single immediate poll hit the server before it finished
writing to the DB, received status='generating' with empty content, then
overwrote the SSE-streamed text with the stale empty row and exited.
isStreaming went false and the UI was stuck showing '...'.
Two fixes:
1. Always poll up to 20 times regardless of SSE success. SSE closing
does not mean the server has committed the final row to the DB.
2. When SSE delivered content, only replace state with polled data if
the polled assistant message is complete or has content — this
prevents clobbering streamed text with a stale empty DB row while
the server is still writing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
bvandeusen
98ad9a2557