Merge lane base check: develop 5b5487d68916

Merge lane base check: run the full gate on `develop` at `5b5487d6891678815638c3331827bdb929ab3383` 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 5b5487d68916 red (develop_red reported; focused rerun red). 10 failures in verb/wire route-contract tests for outcome_scan/benchmark/production_qa/compliance, likely from #7814's toolbox route fold (Task 12989). Report upload refused: bad_request.