Merge lane base check: develop d7af811d414b

Merge lane base check: run the full gate on `develop` at `d7af811d414ba8c1cc99004518ce86eeb91614da` 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 d7af811: develop_red reported (full gate 2×, only Docs site build + link check failed: PR #6997's 'Jaah terms of service' title). Already fixed on develop by 2d0511c (#7006, head edbbb64). Nothing merged/ejected by this check. Memory: none applied.