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.
- Allow users to select a transparent color for logo images (watermarks) via UI (checkbox, color picker, preview).
- Apply color-key transparency in both System.Drawing and ImageSharp backends: specified color in logo is made fully transparent.
- Persist transparency settings in PicSettings and SettingsDto; bind to DataModel and UI controls.
- Update logo preview to reflect transparency in real time.
- Add option to select image processing library (System.Drawing or ImageSharp) in UI and settings.
- Fix bug in SettingsService parameter loading for int/double/DateTime.
- Fully integrate color-key transparency into image processing and settings serialization.
Introduce IImageCreator interface for image creation, and update ImageCreatorSharp to implement it. Add ImageCreatorAlternate (adapter) and ImageCreatorMapper (runtime selector) classes. Extend PicSettings with ImageCreatorProvider to control backend selection. Update DI registrations and refactor ImageCreationStuff to depend on IImageCreator, enabling backend switching via configuration.
