MQTT clients tab: show broker host/port and Tasmota setup hint

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/pages/AdminSettings.tsx

@@ -949,10 +949,15 @@ function MqttClientsTab() {
   const [isService, setIsService] = useState(false)
   const [creating, setCreating] = useState(false)
   const [error, setError] = useState('')
+  const [broker, setBroker] = useState<{ host: string; port: number } | null>(null)
   const [revealed, setRevealed] = useState<{ id: number; username: string; password: string } | null>(null)
   const [copied, setCopied] = useState(false)
 
-  useEffect(() => { load() }, [])
+  useEffect(() => {
+    load()
+    fetch('/settings/api/mqtt-broker', { credentials: 'include' })
+      .then(r => r.ok ? r.json() : null).then(b => b && setBroker(b)).catch(() => {})
+  }, [])
 
   async function load() {
     setLoading(true)
@@ -1057,6 +1062,25 @@ function MqttClientsTab() {
         </button>
       </div>
 
+      {broker && (
+        <div style={{
+          background: 'var(--card-bg)', border: '1px solid var(--card-border)', borderRadius: 'var(--radius)',
+          padding: '0.85rem 1rem', marginBottom: '1.25rem', boxShadow: 'var(--shadow-sm)',
+        }}>
+          <p style={{ fontSize: '0.78rem', fontWeight: 600, color: 'var(--text-mid)', marginBottom: '0.4rem' }}>
+            Point devices at this broker
+          </p>
+          <div style={{ display: 'flex', gap: '1.5rem', flexWrap: 'wrap', fontSize: '0.85rem', color: 'var(--text-dark)' }}>
+            <span>Host <code style={{ background: 'var(--surface-2)', padding: '0.1em 0.4em', borderRadius: 3 }}>{broker.host}</code></span>
+            <span>Port <code style={{ background: 'var(--surface-2)', padding: '0.1em 0.4em', borderRadius: 3 }}>{broker.port}</code></span>
+          </div>
+          <p style={{ fontSize: '0.74rem', color: 'var(--text-mid)', marginTop: '0.4rem' }}>
+            Tasmota: Configuration → Configure MQTT. Enter the host and port above, a client's username and password
+            (use the Password button below), and a unique Topic per switch. The switch must be able to reach this address from its network.
+          </p>
+        </div>
+      )}
+
       {showForm && (
         <form onSubmit={create} style={{
           background: 'var(--card-bg)', border: '1px solid var(--card-border)', borderRadius: 'var(--radius)',