Merge lane base check: develop 08ff5df53d8b

Merge lane base check: run the full gate on `develop` at `08ff5df53d8be129ddf8610dc10f1b35d0eb90db` 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 08ff5df5: develop_red (name-residue K1/K7 double claim from #6998). Fixed on develop by 5182cf6cc (Task 10295); 073e9e7cf passes it. My duplicate fix PR #7028 is closed. Other lane merged #7014–#7026; #7021 still queued. Memory: none applied.