Operates on Service Orders, shown in the Zuper client app as "Work Order" (in every industry). Work Orders share the exact same underlying schema and endpoints as Purchase Orders / Material Orders; they're distinguished only by the purchase_order_type field (SERVICE_ORDER here) and the /service_orders route prefix. Only action: "update_status" is currently supported. The action is processed asynchronously by a background worker — this endpoint acknowledges the request immediately; it does not confirm that every order was updated by the time it responds.