Merge lane base check: develop f585b18daab8

Merge lane base check: run the full gate on `develop` at `f585b18daab8895b45eed6bf42ac1c516ac1f799` 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 f585b18: develop_red. 2 project_memory tests fail (test_propose_relaxation s4_5: Repro line lost when the body is cut, so "needs repro"); they fail again when run alone. Likely the ruff refactor 83c5744c5d. Nothing ejected; queue empty. Memory: none applied