Merge lane base check: develop eb3759b48f6a

Merge lane base check: run the full gate on `develop` at `eb3759b48f6a4f267282a274d0c61b193dc374c2` 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 eb3759b48f6a: develop_red, reported by merge_lane.py run. Full gate: 1 failure in 57,829 tests, still red on a focused rerun: e2e/credentials-filters.spec.ts:201 beforeAll/afterAll 39s hook timeout. Nothing merged or ejected. Memory: none applied.