4x4 sheet, 16 frames. Alignment mirrors VERSUS spriteSheet.ts (union trim:
content ground-line vertical, full-cell-width / cell-center horizontal,
height-fit by trimmed height, anchor 0.5 / 1).
anchorOffsetX is per-character (both A & B); offX/offY/scale are per-sheet
(= timings.<slot>.offsetX / offsetY / scale).