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/appsettings.Development.json

@@ -18,5 +18,9 @@
       "http://localhost:5001",
       "https://localhost:5001"
     ]
+  },
+  "TeleBot": {
+    "ApiUrl": "http://localhost:8080",
+    "ApiKey": "development-key-replace-in-production"
   }
 }