feat: native host bridge integration — C++ bridge, Rust SHM, JS routing, build scripts, docs

- native_bridge/: InstrumentEngineManager multi-channel, sample-accurate, CC/program/pitchbend, transport, Vst3Instrument stub (HAVE_VST3SDK)
- src-tauri: shm.rs, bridge spawn + audio pump + health monitor, open_vst_gui, externalBin, commands
- app: UnifiedMidiRouter, NativeBridgeService, bridgeAudioNode, audioRoutingEngine, Plugin Manager UI, Bridge/WASM indicator, set_position sync
- build: 3 ps1 (force-added, build/ ignored), verify_bundle --check-bridge, CI workflow
- docs: TASKS.md, TEST_NOTES.md (Windows verify checklist), install/report updates

app/static/js/services/runtime.js

@@ -74,6 +74,9 @@ window.SonicRuntime = window.SonicRuntime || { loaded: false, capabilities: null
 window.SonicCarlaMidi = window.SonicCarlaMidi || {
     shouldRoute: function (synthEngine, isArmed) {
         try {
+            // D4: bridge active → VSTi do native bridge host, KHÔNG route Carla
+            // (tránh kép âm).
+            if (window.NativeBridgeService && window.NativeBridgeService.isBridgeConnected) return false;
             var c = window.SonicRuntime && window.SonicRuntime.capabilities;
             if (!c || !c.features || !c.features.carla_local) return false;
             if (!isArmed) return false;
@@ -85,6 +88,8 @@ window.SonicCarlaMidi = window.SonicCarlaMidi || {
     // user đã chủ động bấm Play trên item đó).
     shouldRoutePlayback: function (synthEngine) {
         try {
+            // D4: bridge active → KHÔNG route Carla (bridge host VSTi).
+            if (window.NativeBridgeService && window.NativeBridgeService.isBridgeConnected) return false;
             var c = window.SonicRuntime && window.SonicRuntime.capabilities;
             if (!c || !c.features || !c.features.carla_local) return false;
             var se = synthEngine || {};