feat: Implement push notification system for admin announcements

- Add a notification manager to handle push notifications and integrate with Nostr events.
- Create a push notification service to manage subscription and permission requests.
- Introduce components for notification settings and permission prompts in the UI.
- Update Nostr store to manage push notification state and enable/disable functionality.
- Enhance NostrFeed to send notifications for new admin announcements.
- Implement test notification functionality for development purposes.

src/App.vue

@@ -8,9 +8,10 @@ import { Toaster } from '@/components/ui/sonner'
 import { useNostr } from '@/composables/useNostr'
 import { identity } from '@/composables/useIdentity'
 import { toast } from 'vue-sonner'
-import { config } from '@/lib/config'
+import { useNostrStore } from '@/stores/nostr'
 
 const { isConnected, isConnecting, error, connect, disconnect } = useNostr()
+const nostrStore = useNostrStore()
 
 const showPasswordDialog = ref(false)
 
@@ -43,6 +44,9 @@ onMounted(async () => {
   
   // Connect to Nostr relays
   await connect()
+  
+  // Check push notification status
+  await nostrStore.checkPushNotificationStatus()
 })
 
 onUnmounted(() => {