- NativeInstrumentEngine: track GM bank per channel (CC0/CC32), use bank in programChange
- app.jsx: send CC0/CC32+PROGRAM before notes via __ensureBridgeProgram, dedupe, clear dedupe after async LOAD
- audioRoutingEngine/bridgeAudioNode: idempotent connect (no disconnect-flush on re-connect), fixes note cut & multi-track stuck
- main.cpp: remove 10s poll in OPEN_GUI control job (blocked realtime loop, watchdog race), VstWindowProc stores channel not inst pointer, cleanup gui maps on WM_DESTROY