SDL fallback, partition fix, lz4 remote streaming, delay-oobe-run

SDL display:
- try SDL, auto-fallback to headless if it fails (no crash)
- SDL_VIDEODRIVER=x11 to avoid wayland socket path issues
- suppress XDG_RUNTIME_DIR warnings

Disk copy:
- zap-all before writing to clear old partition tables
- delete recovery partition (4) before resizing partition 3
- use parted resizepart (preserves partition GUID for BCD)
- remote: nix-shell for sgdisk/parted/ntfsresize on target
- remote: lz4 compression for faster streaming
- remote: pv progress bar with disk size
- -y/--yes flag to skip confirmation prompt

Generalize:
- delay-oobe-run=true defers OOBE + activation to real hardware
- clean cached Autounattend from Windows\Panther before sysprep
- taskkill sysprep.exe on first login (CopyProfile artifact)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/images/windows/helpers/makeImage.nix

@@ -53,19 +53,14 @@ let
         export DISPLAY=$(cat "$VMIX_DF")
         export HOME=$(mktemp -d)
         export XDG_RUNTIME_DIR=$HOME
+        export SDL_VIDEODRIVER=x11
         VMIX_DISPLAY="-display sdl"
       fi
     ''}
 
     # Windows installs unattended, reboots into Audit Mode,
     # deletes cached Autounattend, shuts down → QEMU exits.
-    timeout 3600 qemu-system-x86_64 \
-      $VMIX_DISPLAY \
-      -accel kvm \
-      -m ${toString memSize} \
-      -smp ${toString smp} \
-      -cpu host \
-      -machine type=q35 \
+    QEMU_ARGS="-accel kvm -m ${toString memSize} -smp ${toString smp} -cpu host -machine type=q35 \
       -drive if=pflash,format=raw,readonly=on,file=${pkgs.OVMF.fd}/FV/OVMF_CODE.fd \
       -drive if=pflash,format=raw,file=vars.fd \
       -rtc base=localtime,clock=host \
@@ -73,7 +68,16 @@ let
       -drive file=disk.qcow2,format=qcow2,if=virtio \
       -drive file=${iso},media=cdrom,readonly=on \
       -drive file=${drivers.virtio-iso},media=cdrom,readonly=on \
-      -nic user,model=virtio-net-pci
+      -nic user,model=virtio-net-pci"
+
+    timeout 3600 qemu-system-x86_64 $VMIX_DISPLAY $QEMU_ARGS || \
+      if [[ "$VMIX_DISPLAY" == "-display sdl" ]]; then
+        echo "=== vmix: SDL failed, retrying headless ==="
+        cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars.fd && chmod +w vars.fd
+        timeout 3600 qemu-system-x86_64 -nographic $QEMU_ARGS
+      else
+        exit 1
+      fi
 
     echo "=== vmix: ${name} install complete ==="
     mv disk.qcow2 $out