CDN-360: The Replication Queue

CDN-360 converts the CDN-359 active claim ledger into a ranked replication queue. Each active claim receives one receipt-backed replication job with a source receipt hash, ledger event hash, replication mode, priority class, locked decision thresholds, required artifacts, previous job hash, and job hash. The queue assigns one P0 ambiguity discriminator, one P1 near-threshold closure replay, and one P2 high-slack closure replay. The locked result is EVERY_ACTIVE_CLAIM_HAS_A_REPLICATION_JOB.