Cross-platform availability for Compositor, specifically a Windows version.

Hi Robbie,

First of all, thank you for building Compositor and releasing it as open source. A free, Photoshop-style editor with layers, masks, adjustment layers, and non-destructive transforms is exactly what many people are missing, and the workflow-focused feature set looks great.

## Summary

I'd like to request a Windows version of Compositor.

## Motivation

- Many people who are looking for a free Photoshop alternative use Windows, and there are few open source options that feel familiar to Photoshop users (GIMP is powerful, but its workflow and shortcuts are quite different).
- Compositor's focus on compositing and post-processing, with Photoshop-style shortcuts, would be very valuable to that audience.
- A Windows build would grow the user and contributor base, which helps the project long term.

## Context / Challenges

I understand that Compositor is currently a native macOS app built with Xcode and targeting macOS 26, so this is not a simple recompile. Some features (e.g. Content-Aware Fill, Remove Background, Lens Correction) may also rely on platform-specific frameworks. I'm not asking for this to be done quickly, and I completely understand if it is out of scope.

## Possible approaches

Just ideas for discussion, not demands:

1. **Separate Windows port**, reusing the core image-processing logic where possible and rewriting the UI natively (e.g. WinUI/.NET).
2. **Cross-platform rewrite of the core**, with a shared engine (layers, masks, blend modes, transforms...