Retire a catalogue Variant

Retires the variant at expected_generation (409 GENERATION_CONFLICT if it moved): a new try-on naming it is refused, it takes no new revision, and its external_ref is free for a new variant. Retiring is final (409 VARIANT_RETIRED after). A job already admitted from the variant still replays what it was admitted as. Send an Idempotency-Key: a retry with the same key and the same request answers the first response, byte for byte, with Idempotency-Replayed: true, so a response you did not receive is safe to retry. Requires the catalogue.publish scope, which your account operator provisions; no other catalogue scope implies it. Served only where the catalogue is enabled for your environment.