Merge lane base check: develop d7efa26ef68e

Merge lane base check: run the full gate on `develop` at `d7efa26ef68eba55d8f2f2ea3128be774eedf375` 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 d7efa26ef: RED, reported develop_red by merge_lane.py run. Full gate 858s, 58943 passed, 2 jaahd failures confirmed on focused rerun: test_fleet_launch local bin path (compose lines in local launch.sh) and test_main local edition polls no cloud surface (gha-runners scheduled). No PR. Memory: none applied.