Microsoft rotated the unversioned https://dot.net/v1/dotnet-install.ps1, so
the pinned SHA256 was stale and the toolchain aborted ("Possible MITM or
wrong installer version"). Independently re-downloaded the official script
(builds.dotnet.microsoft.com) — its hash matches the guest's observed
value, confirming it is the legitimate current script, not tampering.
Update the pin in both WinBuild2025 and WinBuild2022 toolchains to
6585899AED55FF6AE13DBE1E8C3B878F2D00433520E7EFBE250B75DB948B7DA9 and note
that this pin must be refreshed whenever MS updates the script in place.