`cargo xtask corpus --download` now fetches one full-frame Compressed and
one APS-C Compressed HQ file (about 94 MB) instead of all 12 (about
630 MB); the corpus test checks those two and the lossless-sibling
regression test is gone, since nothing would download those files.
docs/arw6-compression.md keeps the full table with source paths and
SHA-256, says which two xtask fetches and how to fetch the rest with
`curl -L`, and records the CC0 1.0 statement of RawDB's set record
(accessed 2026-10-10).
Co-Authored-By: Claude <noreply@anthropic.com>