dependency_missing· code· HTTP 409· scope bothOne or more exact Event, RealmCommit, predecessor, proof, or other signed dependencies are absent. The response MUST identify the bounded missing set in the operation's closed details/item shape. This is recoverable only through bounded canonical backfill/resolve followed by a new evaluation; it is not authorization denial or service unavailability. Dual-registered with the per-item/federation-transaction reason code.