Out-of-process rebuild: Add Helper/HelperPluginHost.h/.cpp — loads plugin, runs processBlock, shows GUI

Source/Helper/HelperPluginHost.h

@@ -0,0 +1,74 @@
+#pragma once
+
+#include <juce_audio_processors/juce_audio_processors.h>
+#include <juce_gui_basics/juce_gui_basics.h>
+#include <thread>
+#include <atomic>
+
+#include "../Shared/SharedAudioBuffer.h"
+
+class HelperPluginHost
+{
+public:
+    HelperPluginHost();
+    ~HelperPluginHost();
+
+    // Plugin lifecycle
+    bool loadPlugin(const juce::String& path, double sampleRate, int blockSize);
+    void unloadPlugin();
+    bool isLoaded() const { return plugin != nullptr; }
+    juce::String getPluginName() const;
+    int getParameterCount() const;
+
+    // Audio processing (shared memory)
+    void setSharedAudio(SharedAudioBuffer* shm, SharedSemaphore* inSem, SharedSemaphore* outSem);
+    void startProcessing();
+    void stopProcessing();
+
+    // Parameters
+    struct ParamInfo {
+        int index;
+        juce::String id;
+        juce::String name;
+        float value;
+        juce::String displayText;
+    };
+    std::vector<ParamInfo> searchParams(const juce::String& keyword) const;
+    std::vector<std::pair<int, float>> getParams(const std::vector<int>& ids) const;
+    bool setParams(const std::map<int, float>& values);
+
+    // GUI
+    void showGui();
+    void hideGui();
+
+    // State
+    juce::String getStateBase64() const;
+    bool setStateBase64(const juce::String& base64State);
+
+    // Configure
+    void configure(double sampleRate, int blockSize, int channels);
+
+    // Param change callback (called when user touches GUI)
+    std::function<void(int index, float value)> onParamChanged;
+
+private:
+    void audioProcessingLoop();
+
+    juce::AudioPluginFormatManager formatManager;
+    std::unique_ptr<juce::AudioPluginInstance> plugin;
+
+    // Audio thread
+    std::thread audioThread;
+    std::atomic<bool> processing{false};
+
+    SharedAudioBuffer* sharedAudio = nullptr;
+    SharedSemaphore* inputSem = nullptr;
+    SharedSemaphore* outputSem = nullptr;
+
+    double currentSampleRate = 44100.0;
+    int currentBlockSize = 512;
+    int currentChannels = 2;
+
+    // GUI window
+    std::unique_ptr<juce::DocumentWindow> guiWindow;
+};