Deleting a group or sub group still used by barang (or a group still
used by sub groups) is refused, because PHP queries inner join on these
codes and would silently hide the orphaned barang. Editing a sub group
only changes its name, matching ajaxdlmpdk.php; changing the code pair
would orphan barang the same way.
Group codes are generated automatically, unlike the old PHP form where
they were typed manually.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>