Adds OpenNest.Avalonia, a throwaway Avalonia 11 app kept out of
OpenNest.sln, to gauge a Linux port. It reads nests through
OpenNest.IO and draws plates with Skia: a port of the desktop's
display paths (cuts, etches, manual lead-ins, filled material),
pan, cursor zoom, fit, hover and selection, beside a plate list and
a drawings DataGrid. --snapshot renders the window to a PNG.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
