[samgbafa]

Implements runtime renewal against the frozen v1 lease and stamp contracts on #546/#545.

• Signs and verifies renewal stamps with canonical DAG-CBOR; runtime-path tests reproduce the pinned linked-lease and stamp vectors byte-for-byte.
• Persists a monotonic renewer identity epoch. A lease and its stamps extend access only while both renewer DID and epoch match the current node identity.
• Renewal is initiated only by the node-internal scheduler. There is no externally reachable renewal trigger; external clients can register owner-signed leases and read status.
• This slice includes renewal, existing revocation, and status only. Stop/re-enable are deferred; the owner's only off switch is lease revocation, which is irreversible.
• docs/runbooks/renewal-leases.md records the KMS-key-change and database-restore availability caveats.
• The renewal lease/stamp specifications, deferred stop/re-enable contract, and all frozen JSON vector files are unchanged from the test: pin owner-signed renewal lease vector #546 base.

Validation on the runtime source: 15 core renewal tests; 237 core encryption-network tests; 2 stamp-vector tests; 2 lease-vector tests; 3 targeted node route tests; workspace formatting, diff check, and all-target Clippy pass. The Renew control-proof regression was observed failing when its guard was removed and passing with the guard restored. The PG14 ICU collation test fails identically on this branch and main d63d4c44; exact-head PostgreSQL 16 workflow run 43000370692 is in progress and required before merge. No merge, deployment, or restart is authorized.

Details: TC-2106