Merge lane base check: develop 936f302e5218

Merge lane base check: run the full gate on `develop` at `936f302e5218234d28f4a9b69c015efde6e41c43` 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 936f302e52 red: full gate 64316 passed, 1 failed — tests/support_agent/test_support_entity_tools.py::test_every_new_tool_leaves_the_database_unchanged_but_its_marked_read (API unit). develop_red reported by merge_lane.py run. Memory: none applied.