Avalonia platform support

Avalonia's architecture allows it to support new platforms with minimal effort because only 10-15% of its codebase is platform-specific. Unlike MAUI, which wraps native UI toolkits, Avalonia uses its own renderer (Skia or Direct2D) to draw pixels directly, making it platform-agnostic. This design enables support for embedded Linux devices without a desktop environment, VNC (implemented in under 200 lines of code), and recently iOS, Android, and Web. The core requirement for any new platform is simply the ability to draw pixels and receive input events.