ContainerView grows deployed_sha (first 12 chars of the rev
that /var/lib/hyperhive/meta/flake.lock currently has locked
for agent-<name>). renderContainers appends a 'deployed:<sha12>'
chip next to the container name + port — title attribute
explains it's the meta-lock sha. degrades gracefully when the
meta repo isn't seeded yet (missing / unparsable lock = empty
map = no chip). new read_meta_locked_revs helper does the JSON
parsing without unwraps.