the chunked inline_record_bodies migration materializes unresolved legacy event bodies into the event_bodies compatibility archive, verifies every record body against its claimed cid, and deletes the blocks keyspace. event_bodies is a finite archive: new writes never add entries, and the retention filter never applies to it. pre-release v10 databases without the final per-migration marker are rejected rather than silently adopted (hydrant-ksf: the v11 history watermark is preserved as counts data, so marker adoption cannot orphan it). issue: hydrant-6vo, hydrant-ksf, hydrant-pkq