vmix CLI, laptop images, SDL display

CLI (nix run .#):
- `vmix build` and `vmix copy` subcommands
- --image, --generalize key=val, --to-disk, --to-remote-disk
- SDL display auto-detected via DISPLAY temp file passthrough
- --print-build-logs for visible build progress
- -S 4k sparse writes for faster disk copy

Images:
- win10.laptop and win11.laptop bundles (no VirtIO, keeps defender/hibernation)
- templates.bundles.laptop shared template list
- win11 adds reg.disableUCPD on top

Build improvements:
- consistent === vmix: === log prefixes
- SDL display via /tmp/.vmix-display-$$ temp file

Env helpers:
- .env-export-vmix-cli-local: vmix alias for local flake

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

lib/images/windows/helpers/makeImage.nix

@@ -30,24 +30,35 @@ let
     inherit AutounattendedXml;
   };
 
+  displayArg = if vncDisplay != null then "-vnc ${vncDisplay}" else null;
+
   drv = pkgs.runCommand "${name}-vmix.qcow2" {
     __noChroot = true;
     requiredSystemFeatures = [ "kvm" ];
     nativeBuildInputs = with pkgs; [ qemu ];
   } ''
-    # create empty disk
+    echo "=== vmix: creating ${diskSize} disk ==="
     qemu-img create -f qcow2 disk.qcow2 ${diskSize}
 
-    # writable UEFI NVRAM so boot order persists across reboots
     cp ${pkgs.OVMF.fd}/FV/OVMF_VARS.fd vars.fd
     chmod +w vars.fd
 
-    echo "=== Starting Windows unattended install (this takes 15-30 minutes) ==="
+    echo "=== vmix: installing ${name} (unattended, 5-10 min) ==="
+
+    VMIX_DISPLAY="-nographic"
+    ${lib.optionalString (displayArg != null) ''VMIX_DISPLAY="${displayArg}"''}
+    ${lib.optionalString (displayArg == null) ''
+      VMIX_DF=$(ls -t /tmp/.vmix-display-* 2>/dev/null | head -1)
+      if [ -n "$VMIX_DF" ]; then
+        export DISPLAY=$(cat "$VMIX_DF")
+        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 \
-      ${if vncDisplay != null then "-vnc ${vncDisplay}" else "-nographic"} \
+      $VMIX_DISPLAY \
       -accel kvm \
       -m ${toString memSize} \
       -smp ${toString smp} \
@@ -63,7 +74,7 @@ let
       -drive file=${drivers.virtio-iso},media=cdrom,readonly=on \
       -nic user,model=virtio-net-pci
 
-    echo "=== Windows install complete (Audit Mode image) ==="
+    echo "=== vmix: ${name} install complete ==="
     mv disk.qcow2 $out
   '';
 in drv // { _vmixOsType = "windows"; }