AHCI storage for laptop images, plaintext password fix

Laptop images now use AHCI storage + e1000 network instead of VirtIO.
This fixes "inaccessible boot device" on real hardware — the AHCI→NVMe
driver transition is handled by Windows, unlike VirtIO→NVMe which isn't.

- makeImage: useAHCI flag switches disk to ide-hd and network to e1000
- customizeImage: auto-detects useAHCI from original image, propagates it
- win10/win11 laptop images: useAHCI = true
- vmix run: --ahci flag for running laptop images in QEMU
- generalize: PlainText password tags in OOBE unattend XML

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

lib/images/windows/helpers/customizeImage.nix

@@ -30,6 +30,7 @@
     customImageName = (if name != "" then name else "custom") + "-${originalImageName}-vmix.qcow2";
     resultImg = "./disk.qcow2";
 
+    isAHCI = originalImage.useAHCI or false;
     hasRegistry = windowsRegistry != "";
     hasAuditScript = auditScript != "";
 
@@ -98,9 +99,11 @@
         -drive if=pflash,format=raw,file=vars.fd \
         -rtc base=localtime,clock=host \
         -device qemu-xhci -device usb-tablet \
-        -drive file=${resultImg},format=qcow2,if=virtio \
+        ${if isAHCI
+          then "-drive file=${resultImg},format=qcow2,if=none,id=disk0 -device ide-hd,drive=disk0"
+          else "-drive file=${resultImg},format=qcow2,if=virtio"} \
         ${cdromArgs} \
-        -nic user,model=virtio-net-pci"
+        -nic user,model=${if isAHCI then "e1000" else "virtio-net-pci"}"
 
       timeout 1800 qemu-system-x86_64 $VMIX_DISPLAY $QEMU_ARGS || \
         if [[ "$VMIX_DISPLAY" == "-display sdl" ]]; then
@@ -127,4 +130,4 @@
     requiredSystemFeatures = [ "kvm" ];
   } // lib.optionalAttrs impure { __noChroot = true; }) builderCommand;
   in
-    builtImage // { _vmixOsType = "windows"; }
+    builtImage // { _vmixOsType = "windows"; useAHCI = isAHCI; }