Function push_clear_rect_for_slot 

fn push_clear_rect_for_slot(
    pending: &mut Vec<PendingClearRect>,
    slot: &AtlasSlot,
)

Queue a clear rect covering the full padded region of an evicted atlas slot.

The slot’s x/y are already inset by GLYPH_PADDING from the allocation origin, so we subtract it back to get the padded top-left corner and add 2 * GLYPH_PADDING to each dimension.