delete_bom_entry() used raw urllib.request instead of self._request(),
bypassing 401 auth clearing and standard error normalization. Replace
with a single _request('DELETE', ..., raw=True) call, matching the
pattern used by all other BOM methods.
Extracted from silo monorepo. Provides SiloClient (HTTP client) and
SiloSettings (abstract config adapter) so both the FreeCAD workbench
and LibreOffice Calc extension share the same API layer.
Includes CATEGORY_NAMES, sanitize_filename, parse_part_number,
get_category_folder_name, and SSL context builder.