Add This Device tab to portal admin settings

src/pages/AdminSettings.tsx

@@ -47,7 +47,7 @@ interface AppRow {
 }
 
 export function AdminSettings({ user }: { user: User }) {
-  const [tab, setTab] = useState<'integrations' | 'rooms' | 'apps'>('integrations')
+  const [tab, setTab] = useState<'integrations' | 'rooms' | 'apps' | 'device'>('integrations')
   const [integrations, setIntegrations] = useState<Integration[]>([])
   const [loading, setLoading] = useState(true)
 
@@ -68,7 +68,7 @@ export function AdminSettings({ user }: { user: User }) {
         </p>
 
         <div style={{ display: 'flex', gap: '0.25rem', marginBottom: '1.75rem', borderBottom: '1px solid var(--card-border)', paddingBottom: '0' }}>
-          {(['integrations', 'rooms', 'apps'] as const).map(t => (
+          {(['integrations', 'rooms', 'apps', 'device'] as const).map(t => (
             <button key={t} onClick={() => setTab(t)} style={{
               background: 'none', border: 'none', padding: '0.5rem 1rem',
               fontSize: '0.85rem', fontWeight: 600, cursor: 'pointer',
@@ -76,7 +76,7 @@ export function AdminSettings({ user }: { user: User }) {
               borderBottom: tab === t ? '2px solid var(--navy)' : '2px solid transparent',
               marginBottom: '-1px',
             }}>
-              {t === 'integrations' ? 'Integrations' : t === 'rooms' ? 'Rooms & Sites' : 'App Settings'}
+              {t === 'integrations' ? 'Integrations' : t === 'rooms' ? 'Rooms & Sites' : t === 'apps' ? 'App Settings' : 'This Device'}
             </button>
           ))}
         </div>
@@ -95,6 +95,7 @@ export function AdminSettings({ user }: { user: User }) {
 
         {tab === 'rooms' && <RoomsTab />}
         {tab === 'apps' && <AppsTab />}
+        {tab === 'device' && <DeviceTab />}
       </main>
     </div>
   )
@@ -554,6 +555,77 @@ function AppsTab() {
   )
 }
 
+const TIMEOUT_OPTIONS = [
+  { label: 'Off',    value: 0  },
+  { label: '5 min',  value: 5  },
+  { label: '10 min', value: 10 },
+  { label: '15 min', value: 15 },
+  { label: '30 min', value: 30 },
+]
+
+function getInactivityMins(): number {
+  const c = document.cookie.split(';').map(s => s.trim()).find(s => s.startsWith('hnf_inactivity_mins='))
+  return c ? parseInt(c.split('=')[1]) || 0 : 0
+}
+
+function setInactivityMins(mins: number) {
+  document.cookie = mins > 0
+    ? `hnf_inactivity_mins=${mins}; max-age=31536000; path=/; SameSite=Strict`
+    : 'hnf_inactivity_mins=; max-age=0; path=/; SameSite=Strict'
+}
+
+function DeviceTab() {
+  const [inactivityMins, setInactivityMinsState] = useState(getInactivityMins)
+  const [saved, setSaved] = useState(false)
+  const isPwa = window.matchMedia('(display-mode: standalone)').matches
+
+  return (
+    <div style={{ maxWidth: '480px' }}>
+      <p style={{ fontSize: '0.83rem', color: 'var(--text-mid)', marginBottom: '1.5rem' }}>
+        {isPwa
+          ? 'This device is running as an installed PWA — inactivity timeout is automatically disabled. Sessions last until the 30-day sign-in limit.'
+          : 'Set an inactivity timeout for this device. Users will be signed out automatically after the chosen period of no activity. Use on shared or front-desk computers. Ignored when running as an installed PWA.'}
+      </p>
+
+      <p style={{ fontSize: '0.72rem', fontWeight: 700, color: 'var(--text-mid)',
+        textTransform: 'uppercase', letterSpacing: '0.08em', marginBottom: '0.75rem' }}>
+        Inactivity timeout
+      </p>
+
+      <div style={{ display: 'flex', gap: '0.5rem', flexWrap: 'wrap', marginBottom: '1.25rem' }}>
+        {TIMEOUT_OPTIONS.map(opt => (
+          <button
+            key={opt.value}
+            disabled={isPwa}
+            onClick={() => {
+              setInactivityMins(opt.value)
+              setInactivityMinsState(opt.value)
+              setSaved(true)
+              setTimeout(() => setSaved(false), 2000)
+            }}
+            style={{
+              padding: '0.4rem 1rem', borderRadius: '6px', fontSize: '0.85rem', fontWeight: 600,
+              cursor: isPwa ? 'not-allowed' : 'pointer', opacity: isPwa ? 0.4 : 1,
+              border: `1px solid ${inactivityMins === opt.value ? 'var(--navy)' : 'var(--card-border)'}`,
+              background: inactivityMins === opt.value ? 'var(--navy)' : 'var(--body-bg)',
+              color: inactivityMins === opt.value ? '#fff' : 'var(--text-dark)',
+              transition: 'all 0.15s',
+            }}
+          >
+            {opt.label}
+          </button>
+        ))}
+      </div>
+
+      {saved && (
+        <p style={{ fontSize: '0.82rem', color: '#16a34a' }}>
+          ✓ Saved — takes effect immediately
+        </p>
+      )}
+    </div>
+  )
+}
+
 const inputStyle: React.CSSProperties = {
   background: 'var(--body-bg)', border: '1px solid var(--card-border)',
   borderRadius: '6px', padding: '0.45rem 0.75rem', fontSize: '0.85rem',