Refactored image creation APIs to use byte[] for logo data instead of System.Drawing.Image, enabling cross-platform support. Wrapped all GDI+/Windows-specific code in #if WINDOWS and updated project files to conditionally include Windows-only dependencies. Defaulted to ImageSharp on non-Windows, and updated UI and settings to reflect platform capabilities. Application now builds and runs on Linux/macOS with Avalonia and ImageSharp, while retaining full Windows functionality.
Introduce Avalonia as a new cross-platform UI option, including new XAML and code-behind files for the application and main window. Update Program.cs to support a --avalonia launch argument and add corresponding launch profile. Integrate Avalonia NuGet packages and ensure DataModel supports UI-thread invocation for all frontends. All business logic and state are shared via DI, enabling consistent behavior across WinForms, WPF, and Avalonia.
