Function grid 

pub fn grid<C>(children: C) -> Grid<C>
where
    C: PieceSeq,

A SwiftUI-style eager grid (docs/grid.md): columns are inferred from grid_row children — a column is as wide as its widest cell, a grow_w cell makes its column share the leftover width evenly, and a non-row child becomes a full-width cell spanning every column. spacer() inside a row is an inert empty cell that still occupies its column (a grid has explicit gutters, so stack-style push-apart spacers don’t apply). Cells opt into spans and per-cell alignment with [Decorate::grid_span] / [Decorate::grid_align].