Function rank 

pub fn rank(
    ix: &InfonIndex<RoarPostings>,
    facet: &str,
    k: usize,
    noise: &HashSet<String>,
) -> Value

Rank a facet’s values by salience: a min-max-normalised blend of frequency (posting size) and cross-concept breadth (how many distinct structural nodes it co-occurs with). Recency is omitted — the Rust corpus has no reliable per-situation date column — so weights split freq/breadth 0.5/0.5.