fix: route PR notes through bridge when active (VST3/SF2 playback via Play button)

Two guards: schedulePianoRollMidi skips native SF item scheduling while bridge is active; scheduleMidiNoteDispatch lets notes pass to the MIDI router when a piano-roll sub-tab is playing. Verified on Windows: SF2 peak 0.026, VST3 ACDD native GUI + peak 0.074 via Play button. Docs: TEST_NOTES.md, TASKS.md.

app/static/js/app.jsx

@@ -21693,7 +21693,7 @@ const App = () => {
       const startAt = startTime || ctx.currentTime; // undefined/null = phát ngay
       const delayMs = Math.max(0, (startAt - ctx.currentTime) * 1000);
       // Guard chống note-on trễ sau Stop: CHỈ khi là timeline (startTime thật).
-      const guardPlay = startTime != null ? function () { return isPlayingRef.current; } : function () { return true; };
+      const guardPlay = startTime != null ? function () { return isPlayingRef.current || (subTabsRef.current && subTabsRef.current.some(s => s.isPlaying)); } : function () { return true; };
       const trkId = track ? track.id : 0;
       // Percussion (bank 128) → router allocateChannel ch 9; melodic → round-robin.
       const isPerc = !!(synthEngine && synthEngine.soundfont_bank === 128);
@@ -22171,7 +22171,7 @@ const App = () => {
     // future (silence when pressing play). Ghost notes are already relative to
     // the item window, so no absolute-session offset is applied anywhere here.
     const routeCarla = shouldRouteCarla(synthEngine);
-    if (isStandaloneSf() && !routeCarla && isSfTrackEngine(synthEngine)) {
+    if (isStandaloneSf() && !routeCarla && isSfTrackEngine(synthEngine) && !(window.SonicMidiRouter && window.SonicMidiRouter.isBridgeActive())) {
       scheduleNativeSfItem(track, { startTime: 0, notes: midiNotes }, offsetSeconds, context, destNode, bpm, { sources: activeSourcesRef.current, isActive: () => !!isPlayingRef.current });
       return; // native render cả tab → audio buffer (không per-note WASM/Carla)
     }