feat(manager): show LAN waiter/manager addresses and pairing QR in App Info

App Info now lists 'Σερβιτόροι (WiFi)' http://<LAN IP> with a QR code
encoding http://<LAN IP>/?pair=<site_id> (phone camera opens the waiter app;
the native app will read the same code) and 'Διαχείριση (WiFi)'
http://<LAN IP>/manager. The LAN IP comes from HOST_IP, else from the
dashboard's own address when opened by IP; otherwise a hint to set HOST_IP.
QRModal takes an optional caption; the legacy waiter-domain QR is unchanged.

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

manager_dashboard/src/pages/Settings/tabs/AppInfoTab.jsx

@@ -302,7 +302,7 @@ function DataTransferSection() {
 }
 
 
-function QRModal({ url, onClose }) {
+function QRModal({ url, caption = 'Σαρώστε με το κινητό για σύνδεση στο σύστημα.', onClose }) {
   return (
     <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60" onClick={onClose}>
       <div
@@ -314,15 +314,29 @@ function QRModal({ url, onClose }) {
         <div className="p-3 bg-white border border-gray-200 rounded-xl">
           <QRCodeSVG value={url} size={220} includeMargin={false} />
         </div>
-        <p className="text-xs text-gray-400 text-center">
-          Σαρώστε με το κινητό για σύνδεση στο σύστημα.
-        </p>
+        <p className="text-xs text-gray-400 text-center">{caption}</p>
         <button onClick={onClose} className="btn w-full text-sm">Κλείσιμο</button>
       </div>
     </div>
   )
 }
 
+const IPV4 = /^\d{1,3}(\.\d{1,3}){3}$/
+
+// Address phones use on the LAN. HOST_IP from the server wins; otherwise, if this
+// dashboard was itself opened by IP (http://192.168.x.x:8081), that IP is the server.
+function resolveLanIp(status) {
+  if (status?.lan_ip) return status.lan_ip
+  const host = window.location.hostname
+  return IPV4.test(host) && !host.startsWith('127.') ? host : null
+}
+
+// Pairing URL: opens the waiter app when scanned with the phone camera, and the
+// native app reads the same code (?pair=<site_id>) to pair with this venue.
+function waiterPairUrl(lanIp, siteId) {
+  return `http://${lanIp}/` + (siteId ? `?pair=${encodeURIComponent(siteId)}` : '')
+}
+
 function formatUptime(seconds) {
   const h = Math.floor(seconds / 3600)
   const m = Math.floor((seconds % 3600) / 60)
@@ -334,7 +348,7 @@ export default function AppInfoTab() {
   const user = useAuthStore(s => s.user)
   const qc = useQueryClient()
   const [refreshing, setRefreshing] = useState(false)
-  const [qrOpen, setQrOpen] = useState(false)
+  const [qr, setQr] = useState(null)  // { url, caption } | null
   const { data: status, isLoading } = useQuery({
     queryKey: ['system-status'],
     queryFn: () => client.get('/api/system/status').then(r => r.data),
@@ -414,13 +428,46 @@ export default function AppInfoTab() {
               <div className="font-medium text-gray-800">{new Date(status.expires_at).toLocaleDateString('el-GR')}</div>
             </>
           )}
+          {(() => {
+            const lanIp = resolveLanIp(status)
+            if (!lanIp) {
+              return (
+                <>
+                  <div className="text-gray-500">Τοπική πρόσβαση</div>
+                  <div className="text-xs text-amber-700">
+                    Άγνωστη IP του server — ορίστε <span className="font-mono">HOST_IP</span> στο .env
+                  </div>
+                </>
+              )
+            }
+            const pairUrl = waiterPairUrl(lanIp, status?.site_id)
+            return (
+              <>
+                <div className="text-gray-500">Σερβιτόροι (WiFi)</div>
+                <div className="flex items-center gap-2 flex-wrap">
+                  <span className="font-medium text-gray-800 text-xs font-mono break-all">http://{lanIp}</span>
+                  <button
+                    onClick={() => setQr({
+                      url: pairUrl,
+                      caption: 'Σαρώστε με την κάμερα του κινητού — ανοίγει την εφαρμογή σερβιτόρου. Το κινητό πρέπει να είναι στο ίδιο WiFi.',
+                    })}
+                    className="flex items-center gap-1 h-6 px-2 rounded-md border border-gray-300 bg-white text-gray-600 text-xs font-medium hover:bg-gray-50 transition-colors flex-shrink-0"
+                  >
+                    QR Code
+                  </button>
+                </div>
+                <div className="text-gray-500">Διαχείριση (WiFi)</div>
+                <div className="font-medium text-gray-800 text-xs font-mono break-all">http://{lanIp}/manager</div>
+              </>
+            )
+          })()}
           {status?.waiter_domain && (
             <>
               <div className="text-gray-500">Waiter Domain</div>
               <div className="flex items-center gap-2 flex-wrap">
                 <span className="font-medium text-gray-800 text-xs font-mono break-all">{status.waiter_domain}</span>
                 <button
-                  onClick={() => setQrOpen(true)}
+                  onClick={() => setQr({ url: status.waiter_domain })}
                   className="flex items-center gap-1 h-6 px-2 rounded-md border border-gray-300 bg-white text-gray-600 text-xs font-medium hover:bg-gray-50 transition-colors flex-shrink-0"
                 >
                   QR Code
@@ -450,9 +497,7 @@ export default function AppInfoTab() {
         </div>
       )}
 
-      {qrOpen && status?.waiter_domain && (
-        <QRModal url={status.waiter_domain} onClose={() => setQrOpen(false)} />
-      )}
+      {qr && <QRModal url={qr.url} caption={qr.caption} onClose={() => setQr(null)} />}
     </div>
   )
 }