TyrianGbaPoc v89 - Full 9-Channel Audio Release

TyrianGbaPoc v89

This is the first release after the project moved from a technical proof of
concept toward a broadly complete, source-faithful GBA port. The release ROM
uses the production LOW detail profile, Normal game speed, normal campaign
equipment, and no invincibility override.

Highlights

• Complete nine-channel TYM/OPL2 music conversion for all 41 tracks. Earlier
  builds retained at most eight channels; 26 tracks regain an authored voice.
• Procedural percussion now runs at the native 15,768 Hz Maxmod output rate.
  Original SFX and voices remain at their source-native rate to avoid fake
  upsampling.
• Full 18-slot mixer budget: nine music voices, eight logical SFX voices, and
  one spare slot.
• Source-authored Twiddle commands and hidden weapons, including Hot Dog and
  Banana Blast behaviour, are restored alongside the physical GBA mapping.
• Cartridge resources were audited and deduplicated without removing the
  stock data needed for later campaign and seasonal parity work.
• Includes the accumulated boss/OAM scheduling, cache-isolation, fixed-ground
  attachment, menu preview, palette, save/load, and campaign-flow fixes since
  v88.

Validation

• JukeBox flow: PASS (44 modules, circular switching, fade-out and title-music
  restore).
• LOW full-loadout stress, 600 VBlanks: music active and 0 audio-frame loss.
• Audio build audit: 41 tracks, 334 calibrated OPL sources, 0 clipped samples.
• ROM: 27,090,252 bytes (25.835 MiB), safely below the 32 MiB GBA limit.

SHA-256 checksums are provided as a separate release asset.

Notes

• A .sav file is not bundled; the game creates normal SRAM state on first
  use.
• This is an independent fan port and not an official Tyrian release. Tyrian
  and its original assets remain the property of their respective rights
  holders. See THIRD_PARTY_NOTICES.md in the source repository.