Sprint 1: Add PluginBridgeProcessor.h — audio passthrough shell

Source/PluginBridgeProcessor.h

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <juce_audio_processors/juce_audio_processors.h>
+#include <juce_dsp/juce_dsp.h>
+#include "McpServer.h"
+
+class PluginBridgeProcessor : public juce::AudioProcessor
+{
+public:
+    PluginBridgeProcessor();
+    ~PluginBridgeProcessor() override;
+
+    // AudioProcessor interface
+    void prepareToPlay(double sampleRate, int samplesPerBlock) override;
+    void releaseResources() override;
+    void processBlock(juce::AudioBuffer<float>&, juce::MidiBuffer&) override;
+
+    // Editor
+    juce::AudioProcessorEditor* createEditor() override;
+    bool hasEditor() const override { return true; }
+
+    // Plugin identity
+    const juce::String getName() const override { return "PluginBridge"; }
+    bool acceptsMidi() const override { return true; }
+    bool producesMidi() const override { return true; }
+    double getTailLengthSeconds() const override { return 0.0; }
+
+    // Programs (unused)
+    int getNumPrograms() override { return 1; }
+    int getCurrentProgram() override { return 0; }
+    void setCurrentProgram(int) override {}
+    const juce::String getProgramName(int) override { return {}; }
+    void changeProgramName(int, const juce::String&) override {}
+
+    // State
+    void getStateInformation(juce::MemoryBlock& destData) override;
+    void setStateInformation(const void* data, int sizeInBytes) override;
+
+    // MCP server access (for editor status display)
+    bool isMcpServerRunning() const;
+    int getMcpServerPort() const;
+
+private:
+    McpServer mcpServer;
+    static constexpr int kDefaultMcpPort = 16620;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginBridgeProcessor)
+};