feat: implement pwa push notifications

public/push-sw.js

@@ -0,0 +1,43 @@
+self.addEventListener('push', function (event) {
+    if (!event.data) return;
+
+    try {
+        const data = event.data.json();
+        const title = data.title || 'Cat Sitting Planner';
+        const options = {
+            body: data.body || '',
+            icon: '/icon.png',
+            badge: '/icon.png',
+            data: {
+                url: data.url || '/'
+            }
+        };
+
+        event.waitUntil(
+            self.registration.showNotification(title, options)
+        );
+    } catch (err) {
+        console.error('Error processing push event:', err);
+    }
+});
+
+self.addEventListener('notificationclick', function (event) {
+    event.notification.close();
+    event.waitUntil(
+        clients.matchAll({ type: 'window', includeUncontrolled: true }).then(windowClients => {
+            const urlToOpen = event.notification.data.url;
+
+            // Check if there is already a window/tab open with the target URL
+            for (let i = 0; i < windowClients.length; i++) {
+                const client = windowClients[i];
+                if (client.url === urlToOpen && 'focus' in client) {
+                    return client.focus();
+                }
+            }
+            // If not, open a new window
+            if (clients.openWindow) {
+                return clients.openWindow(urlToOpen);
+            }
+        })
+    );
+});