Merge lane base check: develop dfbb35a85300

Merge lane base check: run the full gate on `develop` at `dfbb35a853003193e87f057ab1707f7d7a0dfa30` 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.

develop dfbb35a85300 red (reported develop_red): test_app_token_field… expects old /types shape after 91ce9818e1 (Task 12883) added connect_filled; already fixed on develop by e73110f49d (Task 12903, PR #7790). Memory: none applied.