WordPress Plugin Fix: Sanitize Callback No Longer Strips Saved Facet Mappings
Facet Mapping saves persist correctly. A legacy sanitize callback in the WordPress plugin was silently stripping every saved row under the
sanitize_option_opensolr_settings filter — saves looked successful but the data never made it to the database. Fixed: the callback now handles the new rich mapping shape AND auto-promotes any legacy rows on first save.