ConstThis is a PREVIEW, not the grid renderer: one cell, no measurement, no editing, no overflow into
neighbors. It reads fill / font / border / alignment off an IStyle and paints them directly, so
it stays truthful to the workbook's theme without paying for a grid.
It adopts the GRID surface (data-sxl-theme-surface="grid") and the grid's light/dark mode even
when it renders inside app chrome — a preview of a cell has to resolve auto colors the way that
cell will, not the way the toolbar around it does.
A single cell rendered as plain DOM from the model's own CSS — the swatch behind the cell-styles gallery and the format panels' preview.