Round 1 review (PR #910):
- BLOCKING: add document_ocr_mode / _batch_poll_seconds / _batch_max_wait_seconds
to config._field_map — without it dynaconf silently ignored the env vars and
DOCUMENT_OCR_MODE=batch could never be enabled in production. Add a regression
test asserting the three round-trip from env.
- migration 008: give batch_ocr_jobs a composite PRIMARY KEY on
(user_id, doc_id, doc_type, etag) instead of a bare UniqueConstraint (N1).
- OcrProcessor: use a dedicated _batch_client_lock instead of sharing the sync
backend lock (N3).
- tests: use https:// gateway URLs in the new fixtures to clear SonarCloud's
"insecure http" security hotspots (all 14 were test-only http://gw literals).
1653 unit tests pass; ruff + ty green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>