Initial release — InstaGrain granular synthesizer v1.0

8-voice polyphonic granular synth (VST3/AU/LV2) with:
- 128 grain pool per voice, Hann windowing, linear interpolation
- Root note selector, sample rate correction, sustain pedal (CC64)
- Scatter controls, direction modes (Fwd/Rev/PingPong), freeze
- ADSR envelope, global filter (LP/HP/BP), reverb
- Waveform display with grain visualization
- Drag & drop sample loading, full state save/restore
- CI/CD for Windows/macOS/Linux

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Source/PluginProcessor.h

@@ -0,0 +1,43 @@
+#pragma once
+#include <JuceHeader.h>
+#include "GrainEngine.h"
+
+class InstaGrainProcessor : public juce::AudioProcessor
+{
+public:
+    InstaGrainProcessor();
+    ~InstaGrainProcessor() override;
+
+    void prepareToPlay (double sampleRate, int samplesPerBlock) override;
+    void releaseResources() override;
+
+    bool isBusesLayoutSupported (const BusesLayout& layouts) const override;
+    void processBlock (juce::AudioBuffer<float>&, juce::MidiBuffer&) override;
+
+    juce::AudioProcessorEditor* createEditor() override;
+    bool hasEditor() const override { return true; }
+
+    const juce::String getName() const override { return JucePlugin_Name; }
+    bool acceptsMidi() const override { return true; }
+    bool producesMidi() const override { return false; }
+    bool isMidiEffect() const override { return false; }
+    double getTailLengthSeconds() const override { return 0.0; }
+
+    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 {}
+
+    void getStateInformation (juce::MemoryBlock& destData) override;
+    void setStateInformation (const void* data, int sizeInBytes) override;
+
+    GrainEngine& getEngine() { return engine; }
+
+    std::atomic<bool> bypass { false };
+
+private:
+    GrainEngine engine;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (InstaGrainProcessor)
+};