feat: introduce notification system and claude notifications

public/sw.js

@@ -22,11 +22,9 @@ self.addEventListener('fetch', event => {
   event.respondWith(
     caches.match(event.request)
       .then(response => {
-        // Return cached response if found
         if (response) {
           return response;
         }
-        // Otherwise fetch from network
         return fetch(event.request);
       }
     )
@@ -46,4 +44,53 @@ self.addEventListener('activate', event => {
       );
     })
   );
-});
+  self.clients.claim();
+});
+
+// Push notification event
+self.addEventListener('push', event => {
+  if (!event.data) return;
+
+  let payload;
+  try {
+    payload = event.data.json();
+  } catch {
+    payload = { title: 'Claude Code UI', body: event.data.text() };
+  }
+
+  const options = {
+    body: payload.body || '',
+    icon: '/logo.png',
+    badge: '/logo.png',
+    data: payload.data || {},
+    tag: payload.data?.code || 'default',
+    renotify: true
+  };
+
+  event.waitUntil(
+    self.registration.showNotification(payload.title || 'Claude Code UI', options)
+  );
+});
+
+// Notification click event
+self.addEventListener('notificationclick', event => {
+  event.notification.close();
+
+  const sessionId = event.notification.data?.sessionId;
+  const urlPath = sessionId ? `/session/${sessionId}` : '/';
+
+  event.waitUntil(
+    self.clients.matchAll({ type: 'window', includeUncontrolled: true }).then(clientList => {
+      for (const client of clientList) {
+        if (client.url.includes(self.location.origin)) {
+          client.focus();
+          if (sessionId) {
+            client.navigate(self.location.origin + urlPath);
+          }
+          return;
+        }
+      }
+      return self.clients.openWindow(urlPath);
+    })
+  );
+});