portal: multi-line topic scope input + 'Add topic' on existing MQTT clients

Matches settings' new multi-topic-per-client support: the create form's
Topic scope field is now a textarea (one pattern per line), the list shows
all of a client's scopes, and a '+ Topic' button lets an admin grant an
existing client more topic access without recreating it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/pages/AdminSettings.tsx

@@ -997,6 +997,19 @@ function MqttClientsTab() {
     if (res.ok) load()
   }
 
+  async function addTopic(c: MqttClient) {
+    const topic = prompt(`Add a topic scope to "${c.name}" (e.g. hvac/mhi/#) — existing scopes are kept:`)
+    if (!topic || !topic.trim()) return
+    const res = await fetch(`/settings/api/mqtt-clients/${c.id}`, {
+      method: 'PATCH', credentials: 'include',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ add_topic_scope: topic.trim() }),
+    })
+    const data = await res.json()
+    if (!res.ok) { alert(data.error || 'Failed to add topic'); return }
+    load()
+  }
+
   function copyPassword() {
     if (!created) return
     navigator.clipboard.writeText(created.password)
@@ -1040,9 +1053,12 @@ function MqttClientsTab() {
               placeholder="e.g. Kitchen Flash Reader" style={inputStyle} />
           </label>
           <label style={{ display: 'flex', flexDirection: 'column', gap: '0.3rem' }}>
-            <span style={{ fontSize: '0.78rem', fontWeight: 600, color: 'var(--text-mid)' }}>Topic scope</span>
+            <span style={{ fontSize: '0.78rem', fontWeight: 600, color: 'var(--text-mid)' }}>
-            <input value={topicScope} onChange={e => setTopicScope(e.target.value)}
+              Topic scope
-              placeholder="e.g. utilities/kitchen-meter/# or shellies/#" style={{ ...inputStyle, fontFamily: 'monospace' }} />
+              <span style={{ fontWeight: 400, color: 'var(--text-mid)' }}> — one per line if it needs more than one</span>
+            </span>
+            <textarea value={topicScope} onChange={e => setTopicScope(e.target.value)} rows={2}
+              placeholder={'e.g. shellies/#\nhvac/mhi/#'} style={{ ...inputStyle, fontFamily: 'monospace', resize: 'vertical' }} />
           </label>
           <div style={{ display: 'flex', gap: '1.5rem' }}>
             <label style={{ display: 'flex', alignItems: 'center', gap: '0.4rem', fontSize: '0.85rem', color: 'var(--text-dark)' }}>
@@ -1143,13 +1159,22 @@ function MqttClientsTab() {
                   )}
                 </div>
                 <div style={{ fontSize: '0.72rem', color: 'var(--text-mid)', fontFamily: 'monospace' }}>
-                  {c.topic_scope}
+                  {c.topic_scope.split('\n').join(', ')}
                   <span style={{ marginLeft: '0.6rem', fontFamily: 'sans-serif' }}>
                     {[c.can_publish && 'publish', c.can_subscribe && 'subscribe'].filter(Boolean).join(' + ')}
                   </span>
                 </div>
               </div>
               <div style={{ flexShrink: 0, display: 'flex', gap: '0.5rem', alignItems: 'center' }}>
+                {c.active && (
+                  <button onClick={() => addTopic(c)} title="Add another topic scope to this client" style={{
+                    background: 'transparent', color: 'var(--text-mid)',
+                    border: '1px solid var(--card-border)', borderRadius: '6px',
+                    padding: '0.35rem 0.85rem', fontSize: '0.78rem', fontWeight: 600, cursor: 'pointer',
+                  }}>
+                    + Topic
+                  </button>
+                )}
                 {c.active ? (
                   <button onClick={() => revoke(c)} style={{
                     background: 'transparent', color: 'var(--text-mid)',