Add PC Engine CD / TurboGrafx-16 CD support

[wizzomafizzo]

Summary

Add support for identifying PC Engine CD-ROM² / TurboGrafx-16 CD games.

Background

The PC Engine CD-ROM² (1988) was the first CD-based game console. It uses standard Red Book audio CDs with Yellow Book data tracks, making discs readable by any standard CD/DVD drive.

Technical Details

• Media type: Standard CD (Red Book audio + Yellow Book data)
• Track layout: Track 1 is typically a Mode 1 data track (2048 bytes/sector)
• Identification method:
  • First sector contains header with "PC Engine CD-ROM SYSTEM" or similar identifier
  • Games store metadata in first few sectors of data track
  • No standardized serial number field like PSX/PS2

Proposed ID Method

Since there's no standard serial number, identification would need:

1. Volume label from ISO9660 (when present)
2. First sector signature detection
3. Boot file CRC/hash for unique identification

Implementation Notes

• Can reuse existing ISO9660 parsing infrastructure
• May need custom sector 0 parsing for boot signature
• Database lookup would likely use composite key (volume label + file CRC)

References

• PC Engine CD system documentation
• Related consoles: SuperGrafx, PC-FX (may share format)