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>

qemu/windows11/linux-arm64.ini

@@ -11,28 +11,22 @@
   type = "virt"
 
 # The "virt" machine has no IDE. NVMe and USB mass storage (used by the
-# installation media of --install-from-iso) both have inbox Windows drivers.
+# installation media) both have inbox Windows drivers.
 [device "system_disk-dev"]
   driver = "nvme"
   drive = "system_disk"
   serial = "win11disk"
   bootindex = "1"
 
-# Windows has no inbox driver for virtio-net; the guest tools installed by
-# Configure-Windows.ps1 provide it.
+# Windows has no inbox driver for virtio-net or virtio-gpu, and the base image
+# contains no VirtIO drivers, so the network card is an Intel e1000e and the
+# display is ramfb (a fixed-size framebuffer).
 [device "nic0"]
-  driver = "virtio-net-pci"
+  driver = "e1000e"
   netdev = "net0"
 
-# Unlike q35, "virt" has no default GPU or keyboard. virtio-gpu is the only
-# display, driven by viogpudo (installed by Configure-Windows.ps1). ramfb is not
-# added because Windows would then see a second adapter with a fixed-mode
-# monitor. xres/yres set the preferred mode in the EDID (QEMU defaults to
-# 1280x800); viogpudo accepted 1920x1200 and 2048x1280 but not 2560x1600.
 [device "gpu0"]
-  driver = "virtio-gpu-pci"
-  xres = "2048"
-  yres = "1280"
+  driver = "ramfb"
 
 [device "kbd0"]
   driver = "usb-kbd"