Make Windows Dev Drive setup use existing volumes

Co-authored-by: Codex <noreply@openai.com>

.github/scripts/setup-dev-drive.ps1

@@ -1,35 +1,14 @@
 # Configure a fast drive for Windows CI jobs.
 #
-# If the runner already exposes `D:`, prefer it directly. Otherwise create a
-# small Dev Drive VHD and use that mount point for temp-heavy work.
+# If the runner already exposes `D:`, prefer it directly. Otherwise fall back
+# to `C:` without trying to provision a new volume in CI.
 
 if (Test-Path "D:\") {
     Write-Output "Using existing drive at D:"
     $Drive = "D:"
 } else {
-    try {
-        $VhdPath = "C:/codex_dev_drive.vhdx"
-        $Volume = New-VHD -Path $VhdPath -SizeBytes 20GB -ErrorAction Stop |
-            Mount-VHD -Passthru -ErrorAction Stop |
-            Initialize-Disk -Passthru -ErrorAction Stop |
-            New-Partition -AssignDriveLetter -UseMaximumSize -ErrorAction Stop |
-            Format-Volume -DevDrive -Confirm:$false -Force -ErrorAction Stop
-
-        $Drive = "$($Volume.DriveLetter):"
-
-        fsutil devdrv trust $Drive
-        fsutil devdrv enable /disallowAv
-
-        Dismount-VHD -Path $VhdPath
-        Mount-VHD -Path $VhdPath
-
-        Write-Output $Volume
-        fsutil devdrv query $Drive
-        Write-Output "Using Dev Drive at $Drive"
-    } catch {
-        Write-Warning "Failed to create Dev Drive, falling back to C:. $($_.Exception.Message)"
-        $Drive = "C:"
-    }
+    Write-Warning "No D: drive available; falling back to C:"
+    $Drive = "C:"
 }
 
 $Tmp = "$Drive\codex-tmp"