Fixed compilation error in xref.rs where u64 literal 0x5DEECE66D was used
with u32 state, causing overflow. Changed state to u64 for proper Java
Random algorithm behavior.
The OCG /OCProperties parsing implementation was already complete and
all tests pass. See notes/pdftract-2a6rk.md for verification.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>