Lists complete participations (answers, verbatim, reply, end customer, context, point of sale, state...), most recent first: 20 per page by default, up to 1000 with page_size. Accepts the same filters as /responses: start_date, end_date, date_field, place, survey, source, email, crm_id, has_answers, has_message, has_reply... See Participation retrieval.