fix(safeio): pass valid NT file attributes

tools/tht/internal/safeio/private_root_windows.go

@@ -203,7 +203,11 @@ func openWindowsRelativeObjectWithShareMode(
 		attributes,
 		&status,
 		&allocationSize,
-		windows.FILE_ATTRIBUTE_NORMAL,
+		// NtCreateFile expects zero here for the retained open/create contract. The
+		// Win32 FILE_ATTRIBUTE_NORMAL flag is not a valid NT FileAttributes value
+		// for this RootDirectory-relative call and produces STATUS_INVALID_PARAMETER
+		// on the Windows runner.
+		0,
 		shareMode,
 		disposition,
 		options,