pub fn compose_split(
left: &Frame,
right: &Frame,
left_w: u16,
cols: u16,
focused_left: bool,
) -> FrameExpand description
Stitch two half-width pane frames into one full-width frame:
left cells | divider | right cells per body row, per-pane statuses joined,
right pane’s highlight ranges shifted past the divider, row-level dim
flattened into cells. Pure.