Changes:
- Upgrade both projects from .NET 5.0 to .NET 9.0
- Update Entity Framework Core packages to 9.0.11
- Update SkiaSharp to 3.119.1 (fixes CVE security vulnerability)
- Remove deprecated Microsoft.ApplicationInsights.AspNetCore
- Implement local credential encryption using Data Protection API
- Add CredentialEncryptor helper for DPAPI integration
- Add ConnectionStringManager for secure connection string handling
- Update Startup.cs to register credential encryption services
- Remove Application Insights configuration from _Host.cshtml
All changes maintain backward compatibility with existing plaintext credentials
while providing optional encryption for production deployments.
