Merge lane base check: develop 9c7b0f553efb

Merge lane base check: run the full gate on `develop` at `9c7b0f553efb3c8f8d2e4a7a9e3a5d7f623e2a7d` 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 9c7b0f553efb: RED (develop_red reported). 58076 passed, 1 failed: jaahd test_host_platform_guard — console.py has 0 × '/proc/' but RESIDUAL freezes 1; lower the RESIDUAL entry. Queue empty, nothing merged. Memory: none applied.