Task 5.24: PWA — vite-plugin-pwa with autoUpdate, manifest, workbox caching, PWAInstallPrompt component, notification helper, SVG icons, 6 tests

frontend/src/utils/notifications.ts

@@ -0,0 +1,41 @@
+/**
+ * Notification permission helper — request and check notification permissions (Task 5.24).
+ */
+
+export type NotificationPermissionState = 'default' | 'granted' | 'denied' | 'unsupported';
+
+export function getNotificationPermission(): NotificationPermissionState {
+  if (!('Notification' in window)) return 'unsupported';
+  return Notification.permission as NotificationPermissionState;
+}
+
+export async function requestNotificationPermission(): Promise<NotificationPermissionState> {
+  if (!('Notification' in window)) return 'unsupported';
+  if (Notification.permission === 'granted') return 'granted';
+  if (Notification.permission === 'denied') return 'denied';
+
+  try {
+    const result = await Notification.requestPermission();
+    return result as NotificationPermissionState;
+  } catch {
+    return 'denied';
+  }
+}
+
+export function showNotification(title: string, options?: NotificationOptions): void {
+  if (!('Notification' in window) || Notification.permission !== 'granted') return;
+  try {
+    new Notification(title, options);
+  } catch {
+    // Notification creation can fail in some browsers
+  }
+}
+
+export function isPWAInstalled(): boolean {
+  try {
+    return window.matchMedia('(display-mode: standalone)').matches ||
+      (window.navigator as unknown as { standalone?: boolean }).standalone === true;
+  } catch {
+    return false;
+  }
+}