G0.4: save/restore preset quanh reload khi close GUI (captureState/restoreState, memorystream link truc tiep)

native_bridge/include/INativeInstrument.h

@@ -56,6 +56,10 @@ public:
     // it to dedupe repeated OPEN_GUI (frontend retry spam) — re-attaching a
     // view that is already attached corrupts plugins (Nexus createView→null).
     virtual bool hasAttachedView() const { return false; }
+    // G0.4: serialize/restore the plugin preset across instance reloads
+    // (GUI close/reopen). Non-VST engines: no-op (nothing to save).
+    virtual void captureState() {}
+    virtual void restoreState() {}
 
     // Real-time Audio PCM Float32 rendering loop
     virtual void processAudioBlock(float* outputL, float* outputR, uint32_t numSamples) = 0;

native_bridge/include/Vst3Instrument.h

@@ -9,6 +9,7 @@
 #include "INativeInstrument.h"
 
 #include <string>
+#include <vector>
 
 class Vst3Instrument : public INativeInstrument {
 public:
@@ -27,6 +28,10 @@ public:
     bool openGUI(void* parentWindowHandle) override;
     bool reloadForGUI() override;
     bool attachView(void* parentWindowHandle) override;
+    // G0.4: keep the preset across GUI reopen (reload() recreates the
+    // instance from scratch — without save/restore the plugin resets).
+    void captureState();
+    void restoreState();
     void resizeView(int w, int h) override;
     bool hasAttachedView() const override;
     void closeGUI() override;
@@ -47,6 +52,9 @@ private:
     bool hasAttachedOnce_;
     bool reloading_; // guarded by InstrumentEngineManager::mu_ (set via setReloading)
     uint32_t channel_ = 0;
+    // G0.4: serialized IComponent/IEditController state captured before reload.
+    std::vector<uint8_t> savedComponentState_;
+    std::vector<uint8_t> savedControllerState_;
 };
 
 #endif // VST3_INSTRUMENT_H