The filezilla container on vm-esh-nas shipped with no restart policy. It
was SIGTERMed during the 2026-08-18 host shutdown and never came back,
staying down four days while dockge/dozzle-agent/beszel-agent all
recovered on their own.
- add `restart: unless-stopped` (applied on the host, container recreated
and verified serving 200 on :5800 with all four /NAS mounts visible)
- promote the previously un-canonicalized compose into stacks/filezilla/
so the policy is version-controlled rather than host-only
- record the missing-restart-policy failure mode in the host README
