Add Web Push notifications, PWA support, and full-screen tablet kiosk

Parents get a real push notification when a kid checks off a task
(false->true transitions only, fire-and-forget, degrades gracefully with
no VAPID keys configured). Dashboard is a fully installable iOS/Android
PWA; each child's kiosk link gets its own dynamic per-token manifest so
"Add to Home Screen" opens straight into their board in standalone mode.

Kiosk view is reworked for tablets: safe-area-aware full-bleed layout,
the whole task row is now tappable (previously only the 24px checkbox
was, well under Apple's touch-target minimum), and app icons are
generated by a small dependency-free PNG encoder (no image tooling
available in this environment).

Push requires real HTTPS (iOS Safari won't allow it otherwise) - README
and UNRAID.md cover VAPID setup and the HTTPS prerequisite.

public/js/api.js

@@ -25,5 +25,5 @@ const api = {
   get(path) { return this.request('GET', path); },
   post(path, body) { return this.request('POST', path, body === undefined ? {} : body); },
   patch(path, body) { return this.request('PATCH', path, body === undefined ? {} : body); },
-  del(path) { return this.request('DELETE', path); },
+  del(path, body) { return this.request('DELETE', path, body); },
 };

public/js/calendarRender.js

@@ -49,6 +49,17 @@ function renderCalendar({ calendar, editable, weekdayBoard, weekendWrap, handler
     row.appendChild(cb);
     row.appendChild(span);
 
+    if (!editable) {
+      // Kiosk mode: the 24px checkbox alone is a poor touch target, so the
+      // whole row toggles it. Skip when the tap landed on the checkbox
+      // itself — it already handles its own toggle+change natively.
+      row.addEventListener('click', (e) => {
+        if (e.target === cb) return;
+        cb.checked = !cb.checked;
+        cb.dispatchEvent(new Event('change'));
+      });
+    }
+
     if (editable) {
       span.contentEditable = 'true';
       span.addEventListener('keydown', (e) => {

public/js/push.js

@@ -0,0 +1,103 @@
+function urlBase64ToUint8Array(base64String) {
+  const padding = '='.repeat((4 - (base64String.length % 4)) % 4);
+  const base64 = (base64String + padding).replace(/-/g, '+').replace(/_/g, '/');
+  const rawData = atob(base64);
+  return Uint8Array.from([...rawData].map((c) => c.charCodeAt(0)));
+}
+
+function isIOS() {
+  return /iPad|iPhone|iPod/.test(navigator.userAgent) ||
+    (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1);
+}
+
+function isStandalone() {
+  return window.matchMedia('(display-mode: standalone)').matches || navigator.standalone === true;
+}
+
+const notificationsMessage = document.getElementById('notificationsMessage');
+const notificationsBtn = document.getElementById('notificationsBtn');
+
+function showMessage(text) {
+  notificationsMessage.textContent = text;
+  notificationsMessage.style.display = 'block';
+  notificationsBtn.style.display = 'none';
+}
+
+function showButton(label, onClick) {
+  notificationsMessage.style.display = 'none';
+  notificationsBtn.textContent = label;
+  notificationsBtn.style.display = 'inline-block';
+  notificationsBtn.onclick = onClick;
+}
+
+let cachedPublicKey = null;
+
+async function subscribe() {
+  const reg = await navigator.serviceWorker.ready;
+  const permission = await Notification.requestPermission();
+  if (permission !== 'granted') {
+    return initNotifications();
+  }
+  const sub = await reg.pushManager.subscribe({
+    userVisibleOnly: true,
+    applicationServerKey: urlBase64ToUint8Array(cachedPublicKey),
+  });
+  await api.post('/api/push/subscribe', { subscription: sub.toJSON() });
+  initNotifications();
+}
+
+async function unsubscribe() {
+  const reg = await navigator.serviceWorker.ready;
+  const sub = await reg.pushManager.getSubscription();
+  if (sub) {
+    const endpoint = sub.endpoint;
+    await sub.unsubscribe();
+    await api.del('/api/push/subscribe', { endpoint });
+  }
+  initNotifications();
+}
+
+async function initNotifications() {
+  if (!notificationsMessage) return;
+
+  if (!('serviceWorker' in navigator) || !('PushManager' in window)) {
+    return showMessage('Push notifications aren\'t supported in this browser.');
+  }
+
+  if (!window.isSecureContext) {
+    return showMessage('Notifications require HTTPS. Set up a reverse proxy with a real certificate to use this.');
+  }
+
+  let vapid;
+  try {
+    vapid = await api.get('/api/push/vapid-public-key');
+  } catch {
+    return showMessage('Could not check notification status.');
+  }
+  if (!vapid.enabled) {
+    return showMessage('Push notifications aren\'t configured on this server yet.');
+  }
+  cachedPublicKey = vapid.publicKey;
+
+  if (isIOS() && !isStandalone()) {
+    return showMessage('On iPhone/iPad: tap Share → Add to Home Screen, then open the app icon from your Home Screen and come back here to enable notifications.');
+  }
+
+  if (Notification.permission === 'denied') {
+    return showMessage('Notifications are blocked for this site in your browser settings.');
+  }
+
+  const reg = await navigator.serviceWorker.register('/sw.js');
+  await navigator.serviceWorker.ready;
+  const existingSub = await reg.pushManager.getSubscription();
+
+  if (existingSub) {
+    showButton('Disable notifications on this device', unsubscribe);
+  } else {
+    showButton('Enable notifications on this device', subscribe);
+  }
+}
+
+if (notificationsMessage) {
+  initNotifications();
+}