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/Data/LittleShopContext.cs

@@ -25,6 +25,7 @@ public class LittleShopContext : DbContext
     public DbSet<CustomerMessage> CustomerMessages { get; set; }
     public DbSet<PushSubscription> PushSubscriptions { get; set; }
     public DbSet<Review> Reviews { get; set; }
+    public DbSet<BotContact> BotContacts { get; set; }
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {