Merge lane base check: develop 391d944fb23e

Merge lane base check: run the full gate on `develop` at `391d944fb23e9f3394b7c6ee21da73fe18ab67bc` 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 391d944fb23e: develop_red (gate 2×, 8686 passed). Agent SDK suite: packages/agent-sdk/spec/README.md stale after Task 9182's credential.get text (agent_vocabulary.py:821); re-render alone truncates at "e.g". Queue empty. Memory: none applied.