Add FM Towns Marty support

[wizzomafizzo]

Summary

Add support for identifying FM Towns Marty games.

Background

The FM Towns Marty (1993) was a CD-based Japanese console/computer hybrid by Fujitsu. It uses standard CDs with ISO 9660 filesystem.

Technical Details

• Media type: Standard CD
• Filesystem: Standard ISO 9660
• Region: Japan-only release
• Game library: ~400 titles

Proposed ID Method

1. Use ISO9660 volume label for identification
2. Detect FM Towns-specific boot files
3. Use boot file CRC/hash for unique identification

Implementation Notes

• Standard ISO9660 filesystem - can fully reuse existing parser
• No unique system signature documented (detection may rely on file patterns)
• May need database of known volume labels/boot files
• Lower priority due to smaller game library and limited documentation

Compatibility

• ✅ Readable by standard CD/DVD drives
• Low implementation effort (standard ISO9660)
• Detection reliability depends on file pattern matching

Challenges

• Limited English documentation
• No clear system signature (may need heuristic detection)
• May overlap with general FM Towns computer discs