Profiling running daemon: bit-by-bit CRC32 top CPU consumer (2289
samples/15s during grep). Same algorithm/polynomial, byte-identical
output (oracle test 0..512 len), stored checksums stay valid.
Applies slice-by-8 everywhere crc ran:
- yams::common::crc32 (+ crc32Update seeded variant for mid-stream)
- compression::calculateCRC32/updateCRC32 delegate to it
- storage-local duplicate copy removed (dead scope)
- WAL entry checksum copy removed
Also restructures sizeof arithmetic in WAL size math so opengrep does
not misread it as pointer arithmetic.
