Merge lane base check: develop 0a711709ff55

Merge lane base check: run the full gate on `develop` at `0a711709ff5526ed25884b488c27344975eefc0b` 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).

Certified develop 0a711709ff55: the full gate passed in 600s (55,208 tests passed, 0 failed), event=certified. Nothing merged, nothing ejected, no fix task filed. Memory: none applied.