Function engine_command_reply 

pub fn engine_command_reply(
    cmd: &str,
    arg: &str,
    runtime: &mut Runtime,
    session: &mut Session,
) -> (Value, bool)

handle_engine_command on runtime + the QueryResult value clients render. Returns (value, view_changed). Shared by the actor and the TUI’s ScriptedTransport so both answer identically.