Function sql_success_body 

pub fn sql_success_body(
    results: Vec<Value>,
    cursor: Option<String>,
    single: bool,
    served_by: &str,
) -> Value

Wrap statement results in the common write-authority success envelope. served_by names the authority role that actually answered — "master" on the replicator, "standalone" on a source-less daemon — so observability keyed on routing never invents a replication plane that isn’t there.