[leaves12138]

What changes

A writer that acquires a REST commit lease can leave another writer waiting for expiry if it exits before publishing a snapshot. Add an idempotent POST .../commit-lock/release endpoint and an optional leaseId on acquire and renew. The release request identifies the exact acquisition so delayed cleanup cannot clear a newer lease held by the same writer.

The Java client attempts release when it exits the lease scope, including after a failed or empty operation. Expiry remains the fallback when release cannot reach the server. Catalog servers need to support leaseId and the release endpoint to provide active release. The current rest.commit.acquire-lock option still acquires before each publication attempt.

Verification

• 127 targeted Java tests covering REST signing, Jackson compatibility, lease lifecycle, and snapshot publication. The 12 REST integration cases were rerun after the final fixture adjustment.
• 34 Python DLF signer tests, including parity with Java operation mappings.
• Maven validation, Spotless, and git diff --check.