The old `<Exec Command="COPY ...">` PostBuild step only worked on Windows,
blocking CI on ubuntu-latest. Replaced with two MSBuild `<Copy>` targets:
one AfterTargets="Build" (preserves the existing build-output behavior),
one AfterTargets="Publish" (new — publish output now includes the libs
automatically, so downstream release packaging doesn't need a shell copy
workaround).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>