Round 6 review (PR #910):
- Add the missing propagation test: a transport error (httpx.ConnectError) from
batch submit() propagates out of process() rather than being caught by the sync
OCR try/except or falling back to a sync transcription — guards the intentional
"opted into batch → procrastinate retry, not sync fallback" asymmetry.
- Move the batch-test module imports (BatchPollResult, batch_ocr_store) to the
top of test_ocr_processor.py, dropping the mid-file `# noqa: E402`.
Deferred (reviewer: not actionable for this PR): extracting a lazy-init helper
for the parallel _backend / _batch_client resolution quadruplets.
1653 unit tests pass; ruff + ty green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
