Function subscribe_daemon_lines 

pub fn subscribe_daemon_lines(
    body: Value,
) -> Result<impl Iterator<Item = Result<String, Error>>, Error>

Open a STREAMING daemon connection: send one JSON line, return a line-iterator over the responses. Used by subscribe_task, whose connection stays open (ack line, then NDJSON events until the terminal result) — request_daemon_json reads exactly one line and closes. auth.token is injected from MERMAID_DAEMON_TOKEN like the one-shot path.