Investigation of multi-file extraction hang:
- LocMacNtx(0) returns VNULL for SuperMaster, but V(VNULL) is safe
in the original's virtual memory system (not a null dereference)
- 0xDEDEDEDE is a legacy sentinel for old archives, not the standard
value (original uses masterPrefix=0)
- The hang is in the file data decompression phase, not the cdir
parsing (listing of multi-file archives works correctly)
Multi-file backward compat remains under investigation.