Round 5 review (PR #910), all nits, no blockers:
- _result_from_success: a succeeded job with `pages=[]` (empty list, not just a
missing key) is now a per-document failure ("no pages returned") instead of a
silent 0-chunk success. Test added.
- Comment the deadline-expiry path: the gateway-side job isn't cancelled (no
cancel endpoint at this layer) — it's reaped by the gateway file purge; we just
stop polling it.
- Drop the vestigial status="pending" from the BatchOcrJob test fakes (the column
was removed in round 4; BatchPollResult.status fakes are untouched).
1653 unit tests pass; ruff + ty green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
