Initial commit: InstaDrums VST3 drum sampler plugin

- 12-pad drum sampler with 4x3 grid (expandable by 4)
- Velocity layers with round-robin (Salamander-style filename parsing)
- Rhythm Engine-style GUI: pad grid (left), sample editor (right top),
  FX panel (right bottom), master panel (bottom)
- Waveform thumbnails on pads + large waveform in sample editor
- ADSR envelope, pitch, pan per pad
- Drag & drop sample/folder loading
- Kit save/load (.drumkit XML presets)
- Load Folder with smart name matching (kick, snare, hihat, etc.)
- Choke groups, one-shot/polyphonic mode
- Dark modern LookAndFeel with neon accent colors
- Built with JUCE framework, CMake, MSVC 2022

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

Source/DrumPad.h

@@ -0,0 +1,106 @@
+#pragma once
+#include <JuceHeader.h>
+
+class DrumPad
+{
+public:
+    // A single sample with its audio data and source sample rate
+    struct Sample
+    {
+        juce::AudioBuffer<float> buffer;
+        double sampleRate = 44100.0;
+        juce::File file;
+    };
+
+    // A velocity layer: velocity range + multiple round-robin samples
+    struct VelocityLayer
+    {
+        float velocityLow  = 0.0f;   // 0.0 - 1.0
+        float velocityHigh = 1.0f;
+        juce::OwnedArray<Sample> samples;  // round-robin variations
+        int nextRoundRobin = 0;
+
+        Sample* getNextSample()
+        {
+            if (samples.isEmpty()) return nullptr;
+            auto* s = samples[nextRoundRobin % samples.size()];
+            nextRoundRobin = (nextRoundRobin + 1) % samples.size();
+            return s;
+        }
+    };
+
+    DrumPad();
+    ~DrumPad();
+
+    void prepareToPlay (double sampleRate, int samplesPerBlock);
+    void releaseResources();
+
+    // Single sample loading (backwards compatible)
+    void loadSample (const juce::File& file, juce::AudioFormatManager& formatManager);
+
+    // Velocity layer loading from a folder
+    void loadLayersFromFolder (const juce::File& folder, juce::AudioFormatManager& formatManager);
+
+    bool hasSample() const;
+
+    void trigger (float velocity = 1.0f);
+    void stop();
+
+    void renderNextBlock (juce::AudioBuffer<float>& outputBuffer, int startSample, int numSamples);
+
+    // Pad properties
+    juce::String name;
+    int midiNote = 36;
+    float volume = 1.0f;
+    float pan = 0.0f;
+    float pitch = 0.0f;
+    bool oneShot = true;
+    int chokeGroup = -1;
+    juce::Colour colour { 0xff00ff88 };
+
+    // ADSR
+    float attack  = 0.001f;
+    float decay   = 0.1f;
+    float sustain = 1.0f;
+    float release = 0.05f;
+
+    // State
+    bool isPlaying() const { return playing; }
+    juce::String getLoadedFileName() const { return loadedFileName; }
+    juce::File getLoadedFile() const { return loadedFile; }
+    int getNumLayers() const { return layers.size(); }
+
+    const juce::AudioBuffer<float>& getSampleBuffer() const;
+
+private:
+    // Velocity layers (sorted by velocity range)
+    juce::OwnedArray<VelocityLayer> layers;
+
+    // Currently playing sample reference
+    Sample* activeSample = nullptr;
+
+    // Fallback empty buffer for getSampleBuffer when nothing loaded
+    juce::AudioBuffer<float> emptyBuffer;
+
+    double sampleRate = 44100.0;
+    double readPosition = 0.0;
+    bool playing = false;
+    float currentVelocity = 1.0f;
+
+    // ADSR state
+    enum class EnvelopeStage { Idle, Attack, Decay, Sustain, Release };
+    EnvelopeStage envStage = EnvelopeStage::Idle;
+    float envLevel = 0.0f;
+
+    juce::String loadedFileName;
+    juce::File loadedFile;
+
+    void advanceEnvelope();
+    VelocityLayer* findLayerForVelocity (float velocity);
+
+    // Parse velocity tag from filename (e.g. "snare_OH_FF_1" -> FF)
+    static float velocityTagToLow (const juce::String& tag);
+    static float velocityTagToHigh (const juce::String& tag);
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (DrumPad)
+};