v2025.09.27-01-move

Fix Move pixel byte order — use low byte for grayscale

Move stores grayscale in the low byte (chunk[0]) of each 16-bit pixel,
not the high byte (chunk[1]) like RM2. Content pixels like 0xFF00 were
appearing white instead of black, making half the ink invisible.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>