Merge lane base check: develop 459eb1abc7fe

Merge lane base check: run the full gate on `develop` at `459eb1abc7fe14142346a2c49afeb5c26ab70ded` alone and report it certified or red: nothing had certified it since the last attempt. A red verdict files a fix task; it never holds the lane. Filed by the control plane (`app/merge_lane.py::_certify_idle`). How: run `python3 tools/merge_lane.py run` once. It takes this check's batch, gates that commit with the full gate in its sandbox and reports `certified` or `develop_red` itself. Never run the gate by hand: a hand-run green reports nothing, so no certificate is recorded.

Base check develop 459eb1abc7fe: develop_red (lane-reported). 2 DBOS tests failed in API unit: test_durable_enqueue_engine same-workflow-id dedup, token_billing/test_outbox commit+retry. No PR; queue empty.