Merge lane base check: develop c69c1563e0c8

Merge lane base check: run the full gate on `develop` at `c69c1563e0c817890ac756d1facc54e701661b8d` 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 c69c1563e0c8 CERTIFIED. merge_lane.py run full gate green (exit 0, tree 49ca1674b8). Nothing merged/ejected; queue empty, develop green. Deferred: lane parser shows 0 tests (actual 140 pass). Memory: none applied.