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).
