CDN-362: The Replication Update Ledger

CDN-362 formalizes the public update ledger for GCFT replication results. It consumes accepted result receipts from the replication result gate, mutates only the claims backed by valid job-linked evidence, and records rejected submissions as visible no-op audit events. The artifact demonstrates that closure, confirmation, or withdrawal can enter the public claim register only through accepted result receipts with preserved provenance, artifact checks, threshold replay, and chained update hashes.