fix: missing function declaration for addCamera

public/app.js

@@ -315,6 +315,9 @@ function toggleAdv(btn) {
     adv.classList.toggle('hidden');
     btn.textContent = adv.classList.contains('hidden') ? '▸ Advanced' : '▾ Advanced';
 }
+
+// ── Settings: Add / Remove cameras ──
+function addCamera() {
     const ip = prompt('Camera IP address:', '192.168.1.');
     if (!ip) return;
     const id = 'cam_' + ip.split('.').pop();