Single-strip ORFs at 12.8 bits per pixel are 16-byte blocks: ten little-endian
12-bit samples in bytes 0..14 plus a zero pad byte. Main routed them through the
XZ-2 12-bit word path (stripes, magenta cast). New branch before it; the exactly
12.0 bpp XZ-2 branch is unchanged. Layout measured on CC0 files (log and scripts in
data/testing/retry-olympus-e300 and tools/retry-olympus-e300).
RENDER_CACHE_VERSION bumped to 30 (open PRs use up to 29; adjust at merge).
radialmonster
44b126274d