dashboard: deployed sha chip per container

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.

hive-c0re/assets/app.js

@@ -279,6 +279,11 @@
         ));
       }
       head.append(el('span', { class: 'meta' }, `${c.container} :${c.port}`));
+      if (c.deployed_sha) {
+        head.append(el('span',
+          { class: 'meta', title: 'sha currently locked in /meta/flake.lock' },
+          `deployed:${c.deployed_sha}`));
+      }
       li.append(head);
 
       // ── line 2: action buttons ───────────────────────────────────