fix: main playback default program 0 loads MAIN SoundFont

Line 10283 same issue as 10393: when instrumentProgram is
undefined (section cloned tracks), program defaults to 0.
_playNoteFluid calls program_change(ch,0) on FluidSynth,
which loads program 0 from whatever SoundFont is loaded
(MAIN session's SF). Fix: pass undefined -> oscillator
fallback for all tracks without assigned instrument.

app/static/js/app.jsx

@@ -10280,7 +10280,7 @@ const App = () => {
             const noteEndSec = noteStartSec + noteDurSec;
             if (offsetTime < noteEndSec) {
               const durationMs = noteDurSec * 1000;
-              const program = track.instrumentProgram !== undefined ? track.instrumentProgram : 0;
+              const program = track.instrumentProgram;
               if (offsetTime < noteStartSec) {
                 const delay = noteStartSec - offsetTime;
                 const startTime = context.currentTime + delay;

app/static/js/app.precompiled.js

@@ -299,7 +299,7 @@ const createChorusNode=(context,inputNode,outputNode)=>{const dryGain=context.cr
 const getOrCreateTrackNode=(track,context)=>{if(!track)return null;let node=activeTrackNodesRef.current[track.id];if(!node){const gainNode=context.createGain();const volDb=track.volumeDb??0;const volLinear=volDb<=-50?0:Math.pow(10,volDb/20);gainNode.gain.setValueAtTime(volLinear,context.currentTime);const pannerNode=context.createStereoPanner();pannerNode.pan.setValueAtTime((track.pan??0)/100,context.currentTime);pannerNode.connect(context.destination);let fxStopFn;if(track.fxType==='chorus'){const fxInput=context.createGain();gainNode.connect(fxInput);const chorus=createChorusNode(context,fxInput,pannerNode);fxStopFn=chorus.stop;}else if(track.fxType==='reverb'){const fxInput=context.createGain();gainNode.connect(fxInput);createReverbNode(context,fxInput,pannerNode);fxStopFn=null;}else{gainNode.connect(pannerNode);}node={gainNode,pannerNode,fxStopFn};activeTrackNodesRef.current[track.id]=node;}return node.gainNode;};const getOrCreateSubTrackNode=(track,subTrack,context)=>{if(!track||!subTrack)return null;const subKey=track.id+'_sub_'+subTrack.id;let node=activeTrackNodesRef.current[subKey];if(!node){const gainNode=context.createGain();const volDb=subTrack.volumeDb??0;const volLinear=volDb<=-50?0:Math.pow(10,volDb/20);gainNode.gain.setValueAtTime(volLinear,context.currentTime);const parentNode=getOrCreateTrackNode(track,context);gainNode.connect(parentNode);node={gainNode,pannerNode:null};activeTrackNodesRef.current[subKey]=node;}return node.gainNode;};const playMidiPreviewNote=(pitch,velocity=0.8,durationMs=500)=>{if(!window.SonicSF)return;const context=getAudioContext();const tab=subTabs.find(s=>s.id===activeTabRef.current);const trackId=tab?tab.trackId:selectedTrackId;const track=activeTracks.find(t=>t.id===trackId);const destNode=getOrCreateTrackNode(track,context);const program=track?track.instrumentProgram:undefined;var prevCh=window.SonicPianoRoll?window.SonicPianoRoll.getTrackMidiChannel(track,activeTracks):track?track.midiChannel:0;window.SonicSF.playNote(pitch,velocity,durationMs,context.currentTime,program,destNode,prevCh,track?track.synth_engine:undefined);};const startTrackPlayback=offsetTime=>{const context=getAudioContext();const hasSolo=activeTracks.some(t=>t.solo)||soloedTrackId!==null;activeTracks.forEach(track=>{const isPlayable=hasSolo?track.id===soloedTrackId||track.solo:!track.muted;if(!isPlayable)return;const gainNode=getOrCreateTrackNode(track,context);const pannerNode=activeTrackNodesRef.current[track.id].pannerNode;const clips=track.clips&&track.clips.length>0?track.clips:track.buffer?[{id:'default',buffer:track.buffer,startTime:track.startTime||0,name:track.name,speed:track.speed||1.0}]:[];clips.forEach(clip=>{if(!clip.buffer)return;const source=context.createBufferSource();source.buffer=clip.buffer;source.playbackRate.value=clip.speed||1.0;source.connect(gainNode);const clipStart=clip.startTime||0;const clipDuration=clip.buffer.duration/(clip.speed||1.0);const clipEnd=clipStart+clipDuration;if(offsetTime<clipStart){const delay=clipStart-offsetTime;source.start(context.currentTime+delay,0);activeSourcesRef.current.push(source);}else if(offsetTime<clipEnd){const playOffset=offsetTime-clipStart;source.start(context.currentTime,playOffset*(clip.speed||1.0));activeSourcesRef.current.push(source);}});// MIDI items playback
 const midiItems=track.midiItems||[];if((track.type==='MIDI'||midiItems.length>0)&&window.SonicSF){var trkCh=window.SonicPianoRoll?window.SonicPianoRoll.getTrackMidiChannel(track,activeTracks):track.midiChannel!==undefined?track.midiChannel:0;const bpmVal=parseInt(bpm)||120;const secondsPerBeat=60.0/bpmVal;midiItems.forEach(item=>{const itemEndSec=item.startTime+(item.duration||4);const notes=item.notes||[];notes.forEach(note=>{// note start/duration is in beats (for MIDI items)
 const noteStartSec=item.startTime+(note.start_beat||0)*secondsPerBeat;if(noteStartSec>=itemEndSec)return;// skip notes outside item's visual duration
-const noteDurSec=(note.duration_beats||1)*secondsPerBeat;const noteEndSec=noteStartSec+noteDurSec;if(offsetTime<noteEndSec){const durationMs=noteDurSec*1000;const program=track.instrumentProgram!==undefined?track.instrumentProgram:0;if(offsetTime<noteStartSec){const delay=noteStartSec-offsetTime;const startTime=context.currentTime+delay;window.SonicSF.playNote(note.pitch||60,note.velocity||0.8,durationMs,startTime,program,gainNode,trkCh,track.synth_engine);}else{const playOffset=offsetTime-noteStartSec;const remainingDurMs=(noteEndSec-offsetTime)*1000;window.SonicSF.playNote(note.pitch||60,note.velocity||0.8,remainingDurMs,context.currentTime,program,gainNode,trkCh,track.synth_engine);}}});});}// If track has instrumentId set but no MIDI items, create scheduled oscillators
+const noteDurSec=(note.duration_beats||1)*secondsPerBeat;const noteEndSec=noteStartSec+noteDurSec;if(offsetTime<noteEndSec){const durationMs=noteDurSec*1000;const program=track.instrumentProgram;if(offsetTime<noteStartSec){const delay=noteStartSec-offsetTime;const startTime=context.currentTime+delay;window.SonicSF.playNote(note.pitch||60,note.velocity||0.8,durationMs,startTime,program,gainNode,trkCh,track.synth_engine);}else{const playOffset=offsetTime-noteStartSec;const remainingDurMs=(noteEndSec-offsetTime)*1000;window.SonicSF.playNote(note.pitch||60,note.velocity||0.8,remainingDurMs,context.currentTime,program,gainNode,trkCh,track.synth_engine);}}});});}// If track has instrumentId set but no MIDI items, create scheduled oscillators
 if(track.instrumentId&&midiItems.length===0&&track.buffer){// Play audio normally (the buffer has the audio data)
 // This block is intentionally empty - audio clips already play above
 }// SECTION items playback

wiki.md

@@ -539,6 +539,12 @@
 - **Ghi chú/Test (nếu có):** `npm run build` pass. Ctrl+Click+Drag section/MIDI item → copy đến vị trí mới, item không bị selected.
 ---
 
+### [2026-07-28 09:40] Task: Cả main + section MIDI playback không default program 0
+- **Tóm tắt thay đổi:** Thay đổi line 10283 giống line 10393: `instrumentProgram !== undefined ? ... : 0` → `instrumentProgram`. Trước đây main playback cũng default program 0 khi `instrumentProgram` undefined → `_playNoteFluid` gọi `program_change(ch,0)` trên FluidSynth → load program 0 của MAIN SoundFont. Fix: undefined → oscillator fallback.
+- **Các file ảnh hưởng:** `app/static/js/app.jsx`, `app/static/js/app.precompiled.js`
+- **Ghi chú/Test (nếu có):** `npm run build` pass. MIDI items không instrument → oscillator fallback (không load SoundFont). MIDI items có instrument → FluidSynth play đúng program.
+---
+
 ### [2026-07-28 09:37] Task: Section sub-track MIDI playback không default program 0
 - **Tóm tắt thay đổi:** Line 10393 `subTrack.instrumentProgram !== undefined ? subTrack.instrumentProgram : 0` → `subTrack.instrumentProgram`. Trước đây khi `instrumentProgram` undefined (section clone), program default 0 → `_playNoteFluid` gọi `program_change(ch, 0)` trên FluidSynth → load program 0 của MAIN session's SoundFont. Fix: undefined program → `_playNoteFluid` dùng oscillator fallback (không load SoundFont).
 - **Các file ảnh hưởng:** `app/static/js/app.jsx`, `app/static/js/app.precompiled.js`