Streams one JSON line per completed page instead of buffering the
entire result. Emits start/page/error/done events. On per-page
failure, logs the traceback but yields a generic error message and
continues with the next page. Adds X-Accel-Buffering: no and
Cache-Control: no-cache headers for reverse-proxy compatibility.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>