Function bounded_display_lines 

pub fn bounded_display_lines(
    lines: &[DiffDisplayLine],
    max_rows: usize,
) -> Vec<DiffDisplayLine>

Returns a bounded head/tail excerpt of semantic display lines.

The returned vector contains at most max_rows entries. When rows are omitted, one metadata entry (... N lines omitted ...) is inserted between the retained head and tail. Source line numbers and intraline ranges on retained entries are preserved, so callers can render the excerpt without reparsing or inventing positions.