Implement comprehensive notification system for LittleShop

- Add admin PWA push notifications for order management
- Integrate TeleBot customer messaging service
- Add push notification endpoints and VAPID key support
- Implement order status notifications throughout workflow
- Add notification UI components in admin panel
- Create TeleBotMessagingService for customer updates
- Add WebPush configuration to appsettings
- Fix compilation issues (BotStatus, BotContacts DbSet)
- Add comprehensive testing documentation

Features:
- Real-time admin notifications for new orders and status changes
- Customer order progress updates via TeleBot
- Graceful failure handling for notification services
- Test endpoints for notification system validation

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>

LittleShop/Areas/Admin/Views/Shared/_Layout.cshtml

@@ -122,6 +122,7 @@
     <script src="/lib/jquery/jquery.min.js"></script>
     <script src="/lib/bootstrap/js/bootstrap.bundle.min.js"></script>
     <script src="/js/pwa.js"></script>
+    <script src="/js/notifications.js"></script>
     <script src="/js/modern-mobile.js"></script>
     @await RenderSectionAsync("Scripts", required: false)
 </body>