Restores the plain 'dotnet publish' invocations in
Scripts/Windows/Build-WindowsInstaller.ps1. Hardcoding
C:\Program Files\dotnet\dotnet.exe is machine-specific and unrelated
to parallel downloads.
Snapshot GetVisible() on the UI thread before handing off to Task.Run,
preventing InvalidOperationException when parallel downloads modify the
collection concurrently. Also fix installer script to use 64-bit dotnet.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Allamagoosa