Function narrow_rows 

fn narrow_rows(
    rows: Vec<BoardRow>,
    owner: Option<&str>,
    parent: Option<&TaskId>,
    status: Option<TaskStatus>,
    ready: Option<bool>,
) -> Vec<BoardRow>

The list’s narrowing, one definition for the real path and the mock: owner by label, parent by id, status by state, ready by the board’s own mark.