Stamping an Expiration.Days rule as a volume TTL at write time bakes an
irreversible TTL into the object: removing or lengthening the rule later
can't un-expire it, unlike worker-driven expiration. The metadata-only
delete it enables also skips per-chunk DeleteFile, so dead bytes linger in
a not-yet-expired TTL volume with no deleted-byte accounting until the
whole volume ages out.
Gate the resolver on a per-bucket flag, off by default; toggle with the
s3.bucket.lifecycle.fastpath shell command. Default writes take the worker
path: real deletes that honor current policy and let vacuum reclaim space.
