a0a6009a7ff taught liveMarkerProbe to route a missing marker through the
script helper, which pushed the probe closure past the cyclomatic cap.
helperSubject() now says what is asked about (a dead marker body or no
marker: hold id, owner pid, run identity, log label) and keepsGateShut()
holds the "no marker: only `held` blocks" rule. Behaviour unchanged; the
gate tests pass as they did.
Review 5411223284 (open thread: update-marker-gate.ts absent).
e065426cde