🚧 Add broker status page

README.md

@@ -179,12 +179,17 @@ Hardening done beyond the plan:
       accepts them on create)
 - [x] Administration → System page: broker status + restart (the
       §28 restart gap is closed end-to-end from the UI)
+- [x] Broker Status dashboard (§33/§55): $SYS telemetry collected via
+      the existing dynsec MQTT connection (extra $SYS/# subscription +
+      sys-observe role grant at startup), exposed at
+      GET /broker/status and shown on Broker → Status (version,
+      uptime, connected/stored clients, subscriptions, retained
+      messages, message/publish counters, 1-min load averages, bytes)
 - [ ] Audit browsing UI (events are recorded; no viewer page yet)
 - [ ] Forced password-change UI (backend flag + API exist; the frontend
       does not enforce `must_change_password` yet)
 - [ ] Client metadata editing in the UI
 - [ ] ACL simulator (§15)
-- [ ] Dashboard ($SYS monitoring, broker status, §33)
 - [ ] Certificate expiry monitoring
 - [ ] Backup and restore (logical, encrypted, §45)
 - [ ] Configuration drift detection (§48)