Adds the 4 permanent .mount units (family/books/owncloud/audiobooks) and
audiobookshelf-mount-ready.service to the repo backup, which weren't
tracked here yet, and updates the README to document the autofs->permanent
mount fix applied to nas_audiobooks today so a host rebuild doesn't
recreate the broken automount version.
Stale NFS handles inside containers (ESTALE/errno -116) can persist even
after the host-side mount looks healthy, requiring a manual remount +
container restart. Adds systemd mount-ready hooks (BindsTo) to restart
immich_server/calibre/ocis when their NFS mount unit restarts, plus a
5-minute health-check timer that does a real nested read and force-remounts
on staleness. Host files backed up under system-config/nfs-self-heal/ so
they can be reinstalled after a host rebuild.