Show the macOS display window without zoom-to-fit

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

run-windows11.py

@@ -141,7 +141,7 @@ Environment variables:
   WIN11_VM_UEFI_VARS    OVMF variable-store template path (auto-detected if unset)
   WIN11_VM_QEMU_CONFIG  QEMU config template passed to -readconfig
                         (default: qemu/windows11.ini)
-  WIN11_VM_DISPLAY      QEMU display backend (default: cocoa,zoom-to-fit=on on macOS,
+  WIN11_VM_DISPLAY      QEMU display backend (default: cocoa on macOS,
                         gtk elsewhere)
 """)
 
@@ -388,11 +388,10 @@ if installing:
              "-b", str(base_image), str(disk_image), disk_size])
     print(f"Created Windows 11 system disk: {disk_image}")
 
-# cocoa does not scale the guest by default, so the low-resolution installer
-# screen looks tiny on a Retina display; zoom-to-fit stretches it to the window,
-# as UTM does.
+# cocoa shows the guest at its own resolution. Append ,zoom-to-fit=on (via
+# WIN11_VM_DISPLAY) to stretch a low-resolution screen to the window.
 display_backend = env("WIN11_VM_DISPLAY") or (
-    "cocoa,zoom-to-fit=on" if platform.system() == "Darwin" else "gtk")
+    "cocoa" if platform.system() == "Darwin" else "gtk")
 
 # Most of the VM definition lives in the QEMU config template; fill in the
 # file paths and hand the rendered file to QEMU with -readconfig.