Derive Create/Delete/Change node_name from their classes tuple
Eliminates hand-synced node_name/classes pairs flagged by review as a
maintenance risk (editing one without the other silently breaks
parsing/serialization for the missed type). node_name is purely
descriptive metadata on RegistryItem -- xml_subelement_list(_kwarg)
already derive the real XML tag from each class's get_tag_name(), so
classes stays the single source of truth and node_name is now always
in sync with it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
