Move verification logic to generate_pack.py --verify-packs (single
source of truth). test_pack_integrity.py is now a thin wrapper that
calls the CLI. Pipeline step 6/8 uses the same CLI entry point.
Renumber all pipeline steps 1-8 (was skipping from 5 to 8/9).
Update generate_site.py with pack integrity test documentation.
Extract each platform ZIP to tmp/ (real filesystem, not /tmp tmpfs)
and verify every declared file exists at the correct path with the
correct hash per the platform's native verification mode.
Handles ZIP inner content verification (checkInsideZip, md5_composite,
inner ROM MD5) and path collision deduplication.
Integrated as pipeline step 6/8. Renumber all pipeline steps to be
sequential (was skipping from 5 to 8).
