Merge lane base check: develop 382abc20ed32

Merge lane base check: run the full gate on `develop` at `382abc20ed32143df8bf9157849c9451ee2eeb97` 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 382abc20ed32 red (reported develop_red): POSIX-only calls suite fails — apps/jaahd/accounts.py:3194,3205 _force_remove_leaf uses dir_fd= on a macOS/Windows path; introduced by 7e38470c86 (Task 11287, PR #7354). Memory: none applied.