notepat native: GM instrument HUD label + live digit entry, chord-tone highlight, shift-latch sustain master
- persistent on-screen instrument readout: 'NNN Name' (program 1-128) / 'MIDI PASSTHRU' / legacy 'wave <name>'; shows the digit buffer live with a blinking caret as the program number is typed - chord modifiers now light up ALL chord-tone pads on the grid HUD (root full-bright, extensions dimmer), via chordToneMidi scan in drawGrid - shift-linger is now a true latch: lifting the key keeps the note(s) ringing (joins the heldKeys set, same as Enter-latch); same-key re-press toggles off; stopAll/exit clears. Chords latch as a unit. Plus the GM synthesis research dossier (docs/gm-synthesis/): per-instrument synthesis method + cited papers + performant C algorithm for all 128 GM programs (4 family files) and 00-stochasticism.md (bounded organic per-note variation calibrated to the percussion system). Implemented by subagents.