- Drop unused `import time` from inbound.py and `import call` from
test_inbound.py (caught by ruff in CI; would have caught locally if I'd
run it before pushing).
- Rewrite the misleading comment in PollDelivery.run_once: the cursor DOES
advance past handler exceptions (poison-pill resilience). The previous
comment claimed otherwise, which would have confused future readers.
- Drop `_parse_activity_row` from inbound.py's `__all__`. The leading
underscore signals "private helper"; exposing it via `__all__`
contradicted the convention. Tests still import it directly via the
module path.
- Add `test_fetch_inbound_429_retries_via_get_with_retry` — the PR
description claimed branch-coverage of the 429 path but no test
exercised it. Closes the gap.
