Function patch_balloon_hinting 

pub async fn patch_balloon_hinting(
    __arg0: State<Arc<RuntimeApiController>>,
    __arg1: Path<String>,
) -> Result<Response>

PATCH /balloon/hinting/{op} handler. The op is validated against start | status | stop.

Body is ignored upstream (the entire signal lives in the {op} URL segment); we accept any JSON body to stay shape-compatible.