Function group_by_kind 

pub fn group_by_kind<T>(
    ranked: Vec<T>,
    kind: impl Fn(&T) -> &ResourceKind,
    row_budget: usize,
) -> Vec<KindGroup<T>>

Ranked hits arranged into contiguous per-kind groups and trimmed to a row_budget shared round-robin: a palette paints ~10 rows, and an outscoring kind (forty file hits) can otherwise push a correctly-ranked app off the bottom. A lone group is exempt — narrowing to one kind means “show me all of these”. A zero budget keeps everything.