feat: Agents page + secure /api/agent REST (v1.22.0)

- New admin Agents page (nav + /agents route + views/agents.ejs): live list of
  connected theta-agent hosts with CPU/RAM/disk/ZFS/GPU telemetry and online
  status, updated live over socket.io ('agent.telemetry'/'agent.discovery').
- Auth + admin-gate the /api/agent REST router (it was mounted without
  middleware.auth — anyone could list nodes / send commands). The agent
  WebSocket (/api/agent/ws) is unaffected (handled by the raw wss upgrade with
  its own token auth).
- package.json + lockfile bumped to 1.22.0 to match the tag.

Co-Authored-By: Claude <noreply@anthropic.com>

nodejs/routes/index.js

@@ -59,6 +59,12 @@ router.get('/overview', function(req, res) {
   res.render('overview', {...values});
 });
 
+// Connected theta-agent hosts + live telemetry (admin). Data from
+// GET /api/agent/nodes; live updates via socket.io 'agent.*' events.
+router.get('/agents', function(req, res) {
+  res.render('agents', {...values});
+});
+
 router.get('/admin', (req, res) => res.redirect(301, '/overview'));
 router.get('/notifications', (req, res) => res.redirect(301, '/overview'));
 router.get('/dashboard', (req, res) => res.redirect(301, '/overview'));