Windows launcher only creates a differential disk; seed via Unattend.xml

run-windows11.py no longer installs Windows or touches ISO/img files: it
creates a QCOW2 overlay on the base image (made by vm-images/build-windows-base.sh)
and, when the disk is created, mounts seed.iso. Windows reads the Unattend.xml
in its root during the specialize and OOBE passes (host name, account, auto
logon, Remote Desktop) and Configure-Windows.ps1 then installs OpenSSH with the
host's key, turns off Windows Update and copies the installer scripts.

The VM hardware uses devices with inbox Windows drivers (IDE/NVMe, e1000e,
ramfb on arm64), since the base image has no VirtIO drivers. Autounattend.xml
moves to vm-images; the vm-images pointer is updated.

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

seediso/windows11/Configure-Windows.ps1

@@ -1,5 +1,4 @@
 param(
-    [switch]$InstallVirtIO,
     [switch]$EnableAutomaticLogon,
     [switch]$DisableAutoUpdate,
     [switch]$CopyInstallers,
@@ -35,72 +34,6 @@ if (-not (Test-Administrator)) {
     exit $elevated.ExitCode
 }
 
-# The guest tools installer is an x86 program and the VirtIO ISO has no Arm64
-# package for it, so on Arm64 Windows the Arm64 drivers are installed from their
-# folders on the ISO instead. NetKVM is the network driver; without it the guest
-# has no network.
-function Install-VirtIOArm64Drivers {
-    $roots = (Get-PSDrive -PSProvider FileSystem).Root
-    $drivers = @(
-        @{ Folder = 'NetKVM'; Inf = 'netkvm.inf' },
-        @{ Folder = 'vioserial'; Inf = 'vioser.inf' },
-        @{ Folder = 'Balloon'; Inf = 'balloon.inf' },
-        @{ Folder = 'viorng'; Inf = 'viorng.inf' },
-        @{ Folder = 'vioinput'; Inf = 'vioinput.inf' },
-        @{ Folder = 'viogpudo'; Inf = 'viogpudo.inf' }
-    )
-
-    $installed = 0
-    foreach ($driver in $drivers) {
-        $inf = $roots |
-            ForEach-Object { Join-Path $_ "$($driver.Folder)\w11\ARM64\$($driver.Inf)" } |
-            Where-Object { Test-Path -LiteralPath $_ } |
-            Select-Object -First 1
-        if (-not $inf) {
-            if ($driver.Folder -eq 'NetKVM') {
-                throw 'The Arm64 NetKVM driver was not found on the attached media.'
-            }
-            continue
-        }
-
-        & pnputil.exe /add-driver $inf /install | Out-Host
-        # 3010 asks for a restart; 259 means that no device uses the driver.
-        if ($LASTEXITCODE -notin 0, 259, 3010) {
-            throw "pnputil failed to install $inf (exit code $LASTEXITCODE)."
-        }
-        $installed++
-    }
-    Write-Host "Installed $installed VirtIO Arm64 driver packages."
-}
-
-function Install-VirtIOGuestTools {
-    if ([Runtime.InteropServices.RuntimeInformation]::OSArchitecture -eq 'Arm64') {
-        Install-VirtIOArm64Drivers
-        return
-    }
-
-    $installer = Get-ChildItem `
-        -Path (Get-PSDrive -PSProvider FileSystem).Root `
-        -Filter 'virtio-win-guest-tools.exe' `
-        -File `
-        -ErrorAction SilentlyContinue |
-        Select-Object -First 1
-
-    if (-not $installer) {
-        throw 'virtio-win-guest-tools.exe was not found on the attached media.'
-    }
-
-    $process = Start-Process `
-        -FilePath $installer.FullName `
-        -ArgumentList '/quiet', '/norestart' `
-        -Wait `
-        -PassThru
-
-    if ($process.ExitCode -notin 0, 3010) {
-        throw "VirtIO guest tools installer exited with code $($process.ExitCode)."
-    }
-}
-
 function Enable-AutomaticLogon {
     $winlogonPath = 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon'
 
@@ -205,9 +138,6 @@ function Install-OpenSSHServer {
 
 $exitCode = 0
 try {
-    if ($InstallVirtIO) {
-        Install-VirtIOGuestTools
-    }
     if ($EnableAutomaticLogon) {
         Enable-AutomaticLogon
     }