fix: only send All Notes Off (CC123) when sustain pedal is not active

- Track sustain state per channel via _sustainStates[]
- sustainActive(channel) returns boolean
- MIDI NoteOn: only send CC123 if !sustainActive(ch)
- Preserves sustained notes when playing new notes

app/static/js/app.jsx

@@ -6758,9 +6758,12 @@ const App = () => {
                   activeMidiPitchesRef.current.add(pitch);
                   setActiveMidiPitches(new Set(activeMidiPitchesRef.current));
                    // Stop previous notes on this channel before playing new note
+                   // Only send All Notes Off when sustain pedal is not active
                    { if (window.SonicSF) {
                      const ch = msg.data[0] & 0x0F;
+                     if (!window.SonicSF.sustainActive || !window.SonicSF.sustainActive(ch)) {
                        try { window.SonicSF.controllerChange(ch, 123, 0); } catch (e) {}
+                     }
                      const arSub = subTabsRef && subTabsRef.current && activeTabRef && subTabsRef.current.find(s => s.id === activeTabRef.current && s.type === 'PIANO_ROLL' && s.isArmed);
                     if (arSub) {
                       window.SonicSF.playNote(pitch, velocity, 60000, undefined, arSub.instrumentProgram, null, ch, arSub.synth_engine);

app/static/js/services/soundfontPlayer.js

@@ -36,6 +36,7 @@
     let _initPromise = null;
     let _currentSfId = null;
     const _scheduledNotes = [];
+    const _sustainStates = new Array(16).fill(false);
 
     const SonicSF = {
         loadedFonts: {},
@@ -122,6 +123,9 @@
                 _channels[channel].bank = value;
                 _channels[channel].isPercussion = (value === 128);
             }
+            if (controller === 64) {
+                _sustainStates[channel] = value >= 64;
+            }
         },
 
         programChange: function (channel, program) {
@@ -154,6 +158,11 @@
             return { ..._channels[channel] };
         },
 
+        sustainActive: function (channel) {
+            if (channel < 0 || channel > 15) return false;
+            return _sustainStates[channel];
+        },
+
         pitchBend: function (channel, value) {
             if (channel < 0 || channel > 15) return;
             if (_initialized && _synthInstance) {