LocalFlowRowScope

Carries the innermost FlowRow's Compose FlowRowScope down the tree, or null when no ancestor FlowRow has provided one — read by Modifier.size() to resolve a child's horizontal Weight (via flowRowScope.weight) and vertical FillRow sizing behavior. Provided by FlowRowTileRenderer, which also resets LocalRowScope/LocalLazyItemScope to null; reset back to null in turn by RowTileRenderer/LazyRowTileRenderer.