Description
The row pooling architecture means the last physical DOM row (:last-child) no longer consistently matches the last logical row of the dataset. Therefore, the CSS rule hiding the bottom border for the :last-child row causes missing borders on data rows.

Additionally, the grid scroll height calculation currently includes a + 1 row offset, resulting in an empty row at the bottom of the grid. Since removing the :last-child CSS fix ensures the final data row will always render its own bottom border, this extra scroll space is unnecessary and creates dead space.

Proposed Changes

1. Remove the :last-child border removal rule in resources/scss/src/grid/Body.scss.
2. Remove the + 1 extra row calculation in src/grid/Body.mjs and src/grid/VerticalScrollbar.mjs (updateScrollHeight).