Both consumers live in their own build roots and cannot reach crc32.zig by path, so the export is forced. Adds the differential fuzz lane against std — the only coverage that can see a self-consistent but numerically shifted implementation, which would orphan every existing .zit file.

The implementation brief prohibited this export, citing repocache as the precedent for unexported leaf modules. That precedent does not apply: repocache has no out-of-module consumer. storestat and repoimage, which do, are both exported. Overridden deliberately. closed check-in: c57c16c5cd user: dmestas tags: logstore-index