Confirms the existing proxy streams SSE chunks incrementally: - 5-chunk test with 50ms delays verifies time spread between first and last chunk arrival (not buffered) - Verifies data: [DONE] terminator is forwarded No src/ changes needed — Body::from_stream(bytes_stream()) already handles SSE correctly. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>