fix(lib): ContainsByteSlice never reports a match

[devorun]

Problem

lib.ContainsByteSlice uses a naked return inside the match branch, so the named return value found is never set to true. The function therefore returns false even when target is present in list:

func ContainsByteSlice(list [][]byte, target []byte) (found bool) {
    for _, item := range list {
        if bytes.Equal(item, target) {
            return // found is still false here
        }
    }
    return
}

This helper fills a real gap because slices.Contains cannot operate on [][]byte ([]byte is not comparable), so any current or future caller relying on it would silently get the wrong answer.

Fix

Return true on a match.

Tests

Added TestContainsByteSlice (table-driven, matching the existing style in util_test.go) covering the target present at the head, middle, and tail, plus the empty-list and absent cases. The presence cases fail against the previous implementation and pass with the fix.