feat(notifications): add browser push notifications for calendar events with personal profile settings

sw.js

@@ -0,0 +1,45 @@
+/**
+ * Fociz Service Worker
+ * Beheert desktop push notificaties en click events voor agenda-afspraken.
+ */
+
+self.addEventListener('install', (event) => {
+    self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+    event.waitUntil(self.clients.claim());
+});
+
+// Behandel klik op een notificatie
+self.addEventListener('notificationclick', (event) => {
+    event.notification.close();
+
+    const targetUrl = (event.notification.data && event.notification.data.url) 
+        ? event.notification.data.url 
+        : '/planner.php';
+
+    event.waitUntil(
+        clients.matchAll({ type: 'window', includeUncontrolled: true }).then((windowClients) => {
+            // Als er al een Fociz tabblad open staat, breng die naar voren
+            for (let i = 0; i < windowClients.length; i++) {
+                const client = windowClients[i];
+                if ('focus' in client) {
+                    if (targetUrl.startsWith('http') && !targetUrl.includes(self.location.host)) {
+                        // Externe meeting link (zoals Teams): open in nieuw tabblad
+                        if (clients.openWindow) {
+                            return clients.openWindow(targetUrl);
+                        }
+                    } else {
+                        client.navigate(targetUrl);
+                        return client.focus();
+                    }
+                }
+            }
+            // Geen tabblad open: open een nieuw venster
+            if (clients.openWindow) {
+                return clients.openWindow(targetUrl);
+            }
+        })
+    );
+});