Validate the fixed 16-byte version-39 records before using their count to select the serialized index width. Reject contradictory count and byte extents while preserving valid zero, one and 300-record controls.
Validation: 89 focused reader/provider/compiled CLI and stdio MCP tests; check:ci; seven reproduced CLI and SDK-validated MCP cases with unchanged fixture hashes. Version-specific source and independent parser evidence distinguish fixed records from compressed indices. Synthetic metadata only; no real-game or target-execution qualification.
Fixes#5751