Install OpenSSH Server from the Win32-OpenSSH zip

Carry the zip for the host architecture in the seed ISO and add
06-Install-OpenSSH-Zip-Admin.bat, which installs from it instead of
Windows Update. Update vm-images.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

seediso/windows11/build-seed.sh

@@ -10,6 +10,13 @@ case "$arch" in
   *) printf 'Error: unsupported architecture: %s\n' "$arch" >&2; exit 1 ;;
 esac
 
+# The OpenSSH zip for the target architecture comes from the shared image
+# helper, which downloads it when missing.
+image_helper="${VM_IMAGE_HELPER:-$script_dir/../../vm-images/download-images.sh}"
+openssh_zip="$(VM_IMAGE_ARCH="$answer_arch" "$image_helper" --print-path openssh-win)"
+[[ -s "$openssh_zip" ]] || VM_IMAGE_ARCH="$answer_arch" "$image_helper" openssh-win
+[[ -s "$openssh_zip" ]] || { printf 'Error: %s was not downloaded.\n' "$openssh_zip" >&2; exit 1; }
+
 # The answer file's components name the processor architecture, so render a
 # copy for the target architecture.
 work_dir="$(mktemp -d)"
@@ -20,6 +27,7 @@ sed "s/processorArchitecture=\"amd64\"/processorArchitecture=\"${answer_arch}\"/
 seed_files=(
   "$work_dir/Autounattend.xml"
   "$script_dir/Configure-Windows.ps1"
+  "$openssh_zip"
 )
 # Numbered installer scripts (10-Install-Git-Admin.bat, 20-..., in install order).
 shopt -s nullglob