v0.4.0

Added

• Multi-instrument MIDI support with GM program detection and auto soundfont mapping
• Per-track controls for visibility, mute, volume, sustain, and waveform/piano-roll toggles
• Track-aware instrument icons, palettes, and color handling for multi-track MIDI files

Changed

• Updated player, visualization, and loop controls to handle multi-track state across audio and UI
• Refreshed file list and wave list UI to expose per-track toggles and multi-file controls
• Improved MIDI parser and sampler manager to keep track metadata consistent across playback and rendering

Tests

• Added coverage for multi-MIDI manager behaviors and instrument family mapping