Windows embedded Python ignores PYTHONPATH when a ._pth file exists.
Add ../app/src to the ._pth so wled_controller is importable.
Fixes ModuleNotFoundError on portable builds.
Replace Windows runner requirement with cross-compilation:
download Windows embedded Python + win_amd64 wheels from PyPI,
package into the same ZIP structure as build-dist.ps1.
All 4 release jobs now run on ubuntu-latest.