Merge lane base check: develop 70f3512c97da

Merge lane base check: run the full gate on `develop` at `70f3512c97dad091aa9eb594b43ce149525ab697` 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.

Base check develop 70f3512c97da: develop_red reported by the lane. Full gate had 3 API unit failures (test_durable_enqueue_engine ×2, test_live_cast_engine ×1); fix task filed by the control plane. Queue empty, nothing ejected. Memory: none applied.