Constant SOURCE_PVC_MISSING_GATE 

pub const SOURCE_PVC_MISSING_GATE: StructuralGate;

A backup whose DIRECT source PVC (spec.sources[].pvc) does not exist at launch time. The Snapshot parks at phase: Pending on the slow structural cadence and, once the controller’s missing-source deadline passes, flips terminally Failed — a PVC that never reappears never self-heals, and only recreating it (or repointing the policy’s sources) can clear the block. Written on the Snapshot only for the direct-source case: a vanished operator-staged claim (copyMethod Snapshot/Clone) is a restage race and stays a plain transient retry, never this gate.