ODDK v0.1.94

Added

• Archives are encrypted at rest. Every snapshot, legacy backup and
  pre-upgrade backup is now written as .tar.zst.age: age
  with a post-quantum hybrid key (ML-KEM-768 + X25519) derived from master.key.
  Someone who can read the backup directory or the offsite bucket but does not
  have master.key learns nothing about the contents, not even instance names.
  There is no new secret: restore and apply use the --master-key they already
  take. There is no setting to turn it off.
• A wrong master key is refused before anything changes, and the error names
  the key the archive needs: the checksum that ends its master.key line.
  snapshot apply now checks the key first, before any other preflight step.
• oddk snapshot decrypt writes the plain .tar.zst out of an encrypted
  archive (verified first, mode 0600). With --print-age-identity it prints the
  derived age secret instead, so the stock age CLI can decrypt with no ODDK
  installed. It runs locally; no daemon needed.

Changed

• Archives written before this release keep their .tar.zst name and stay
  restorable through every path, unchanged.
• An --s3-uri download that this host cannot decrypt is now discarded, because
  it cannot be verified, rather than kept for a retry. Supply the source's
  --master-key and the retry downloads it again.
• A legacy backup restore of a backup written on another host is refused:
  backups have no --master-key. Snapshots are the cross-host path.

Action: without master.key, archives from this release on cannot be
restored or read. Confirm now that master.key is backed up somewhere other
than this host and its bucket.

Action: ODDK versions before 0.1.94 cannot read the new archives. Install
this release or later on any host you would restore or apply to.

Action (optional): archives already in your bucket stay unencrypted
until retention prunes them. To be rid of them sooner, delete them once a newer
encrypted complete snapshot exists (oddk snapshot list,
oddk snapshot remove-remote <id>).