Merge lane base check: develop 5f27a552f5d9

Merge lane base check: run the full gate on `develop` at `5f27a552f5d924612c4ea846ed33f36e3834de4e` 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 (Task 6722).

Base check develop 5f27a552f: develop_red reported. 4 Playwright e2e tests fail and fail again run alone: access-tabs:203, assignment-list:74 (desktop+pixel9proxl), org-limits:14. Nothing merged or ejected; queue empty. Memory: none applied.