Merge lane base check: develop aa00b6555e9c

Merge lane base check: run the full gate on `develop` at `aa00b6555e9c91233b8b01de51aae941299c0f39` 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 certified: full gate green on develop aa00b6555e9c (56,648 passed, 0 failed, 952s; event=certified). Nothing merged or ejected; queue empty; develop green. Memory: none applied.