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/PluginEditor.h

@@ -0,0 +1,58 @@
+#pragma once
+#include <JuceHeader.h>
+#include "PluginProcessor.h"
+#include "PadComponent.h"
+#include "SampleEditorPanel.h"
+#include "FxPanel.h"
+#include "MasterPanel.h"
+#include "LookAndFeel.h"
+
+class InstaDrumsEditor : public juce::AudioProcessorEditor,
+                         private juce::Timer
+{
+public:
+    explicit InstaDrumsEditor (InstaDrumsProcessor&);
+    ~InstaDrumsEditor() override;
+
+    void paint (juce::Graphics&) override;
+    void resized() override;
+
+private:
+    InstaDrumsProcessor& processor;
+    InstaDrumsLookAndFeel customLookAndFeel;
+
+    // Pad grid (left side)
+    juce::OwnedArray<PadComponent> padComponents;
+    static constexpr int padColumns = 4;
+
+    // Right side panels
+    SampleEditorPanel sampleEditor;
+    FxPanel fxPanel;
+
+    // Bottom
+    MasterPanel masterPanel;
+
+    // Top bar buttons
+    juce::TextButton loadSampleButton { "LOAD SAMPLE" };
+    juce::TextButton saveKitButton    { "SAVE KIT" };
+    juce::TextButton loadKitButton    { "LOAD KIT" };
+    juce::TextButton loadFolderButton { "LOAD FOLDER" };
+
+    juce::Label titleLabel { {}, "INSTADRUMS" };
+    juce::Label versionLabel { {}, "v1.0" };
+    juce::Label padsLabel { {}, "DRUM SAMPLER" };
+
+    // State
+    int selectedPadIndex = 0;
+
+    void rebuildPadGrid();
+    void selectPad (int index);
+    void timerCallback() override;
+
+    std::unique_ptr<juce::FileChooser> fileChooser;
+
+    // Resizable
+    juce::ComponentBoundsConstrainer constrainer;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (InstaDrumsEditor)
+};