- Cover the new utilities helpers (unpad, crc32, checksumPid type
preservation, pidFromSerial, safe_join) and drop the now-redundant
per-module crc32 tests.
- Rename test_unpad_removes_pkcs7_padding to reflect that unpad only
trusts the trailing pad-length byte rather than validating PKCS#7.
- Replace the KOBO_HASH_KEYS change-detector with a test that documents
the intentional value pin and checks the ASCII-salt contract.
- Note kgenpids' hybrid import in the test-loader docstring.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>