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.
