Merge lane base check: develop efbf842a91e7

Merge lane base check: run the full gate on `develop` at `efbf842a91e771c29cf8f6e93bf0ecc027fb5ff2` 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`).

develop efbf842a9 was red: one stale vitest snapshot (TaskEditForm tight-width create form, left stale by Task 8117's paperclip Attach). Refreshed it in PR #6343, which merged as d96aaed3e with the full gate passing and Jaah Deploy succeeding. develop is green.