Function handle_get_map_keys 

pub async fn handle_get_map_keys(
    __arg0: State<AppState>,
    headers: HeaderMap,
    __arg2: Query<MapPathQuery>,
) -> Response

GET /api/config/map-keys?path=<section> — list the current alias keys at a map-keyed section path, e.g. channels.discord → ["default","work"].