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/LittleShop.csproj

@@ -17,6 +17,7 @@
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     <PackageReference Include="FluentValidation" Version="11.11.0" />
     <PackageReference Include="FluentValidation.AspNetCore" Version="11.3.0" />
+    <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks.EntityFrameworkCore" Version="9.0.9" />
     <PackageReference Include="Serilog.AspNetCore" Version="8.0.3" />
     <PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="7.0.0" />