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/SampleEditorPanel.cpp

@@ -0,0 +1,144 @@
+#include "SampleEditorPanel.h"
+#include "LookAndFeel.h"
+
+SampleEditorPanel::SampleEditorPanel()
+{
+    titleLabel.setFont (juce::FontOptions (14.0f, juce::Font::bold));
+    titleLabel.setColour (juce::Label::textColourId, InstaDrumsLookAndFeel::textSecondary);
+    addAndMakeVisible (titleLabel);
+
+    padNameLabel.setFont (juce::FontOptions (13.0f, juce::Font::bold));
+    padNameLabel.setColour (juce::Label::textColourId, InstaDrumsLookAndFeel::accent);
+    addAndMakeVisible (padNameLabel);
+
+    waveform.setShowADSR (true);
+    addAndMakeVisible (waveform);
+
+    setupKnob (attackSlider,  attackLabel,  "Attack",  0.0, 1.0, 0.001, 0.001);
+    setupKnob (decaySlider,   decayLabel,   "Decay",   0.0, 2.0, 0.1, 0.01);
+    setupKnob (sustainSlider, sustainLabel, "Sustain", 0.0, 1.0, 1.0, 0.01);
+    setupKnob (releaseSlider, releaseLabel, "Release", 0.0, 2.0, 0.05, 0.01);
+    setupKnob (pitchSlider,   pitchLabel,   "Pitch",  -24.0, 24.0, 0.0, 0.1);
+    setupKnob (panSlider,     panLabel,     "Pan",    -1.0, 1.0, 0.0, 0.01);
+    setupKnob (cutoffSlider,  cutoffLabel,  "Cutoff",  20.0, 20000.0, 20000.0, 1.0);
+    setupKnob (resoSlider,    resoLabel,    "Reso",    0.1, 10.0, 0.707, 0.01);
+
+    cutoffSlider.setSkewFactorFromMidPoint (1000.0);
+}
+
+void SampleEditorPanel::setupKnob (juce::Slider& s, juce::Label& l, const juce::String& name,
+                                    double min, double max, double val, double step)
+{
+    s.setSliderStyle (juce::Slider::RotaryHorizontalVerticalDrag);
+    s.setTextBoxStyle (juce::Slider::NoTextBox, false, 0, 0);
+    s.setRange (min, max, step);
+    s.setValue (val, juce::dontSendNotification);
+    s.addListener (this);
+    addAndMakeVisible (s);
+
+    l.setText (name, juce::dontSendNotification);
+    l.setFont (juce::FontOptions (9.0f));
+    l.setColour (juce::Label::textColourId, InstaDrumsLookAndFeel::textSecondary);
+    l.setJustificationType (juce::Justification::centred);
+    addAndMakeVisible (l);
+}
+
+void SampleEditorPanel::setPad (DrumPad* pad)
+{
+    currentPad = pad;
+    updateFromPad();
+}
+
+void SampleEditorPanel::updateFromPad()
+{
+    if (currentPad == nullptr) return;
+
+    padNameLabel.setText (currentPad->name, juce::dontSendNotification);
+
+    attackSlider.setValue (currentPad->attack, juce::dontSendNotification);
+    decaySlider.setValue (currentPad->decay, juce::dontSendNotification);
+    sustainSlider.setValue (currentPad->sustain, juce::dontSendNotification);
+    releaseSlider.setValue (currentPad->release, juce::dontSendNotification);
+    pitchSlider.setValue (currentPad->pitch, juce::dontSendNotification);
+    panSlider.setValue (currentPad->pan, juce::dontSendNotification);
+
+    auto& buf = currentPad->getSampleBuffer();
+    waveform.setBuffer (&buf);
+    waveform.setColour (currentPad->colour);
+    waveform.setADSR (currentPad->attack, currentPad->decay, currentPad->sustain, currentPad->release);
+
+    repaint();
+}
+
+void SampleEditorPanel::sliderValueChanged (juce::Slider* slider)
+{
+    if (currentPad == nullptr) return;
+
+    if (slider == &attackSlider)       currentPad->attack  = (float) slider->getValue();
+    else if (slider == &decaySlider)   currentPad->decay   = (float) slider->getValue();
+    else if (slider == &sustainSlider) currentPad->sustain = (float) slider->getValue();
+    else if (slider == &releaseSlider) currentPad->release = (float) slider->getValue();
+    else if (slider == &pitchSlider)   currentPad->pitch   = (float) slider->getValue();
+    else if (slider == &panSlider)     currentPad->pan     = (float) slider->getValue();
+
+    // Update ADSR overlay
+    waveform.setADSR (currentPad->attack, currentPad->decay, currentPad->sustain, currentPad->release);
+}
+
+void SampleEditorPanel::paint (juce::Graphics& g)
+{
+    auto bounds = getLocalBounds().toFloat();
+    g.setColour (InstaDrumsLookAndFeel::bgMedium);
+    g.fillRoundedRectangle (bounds, 6.0f);
+    g.setColour (InstaDrumsLookAndFeel::bgLight.withAlpha (0.5f));
+    g.drawRoundedRectangle (bounds, 6.0f, 1.0f);
+}
+
+void SampleEditorPanel::resized()
+{
+    auto area = getLocalBounds().reduced (6);
+
+    // Header
+    auto header = area.removeFromTop (20);
+    titleLabel.setBounds (header.removeFromLeft (100));
+    padNameLabel.setBounds (header);
+
+    area.removeFromTop (2);
+
+    // Waveform (top portion ~40%)
+    int waveHeight = std::max (60, (int) (area.getHeight() * 0.38f));
+    waveform.setBounds (area.removeFromTop (waveHeight));
+
+    area.removeFromTop (4);
+
+    // ADSR knobs row
+    int knobH = std::max (40, (int) (area.getHeight() * 0.45f));
+    auto adsrRow = area.removeFromTop (knobH);
+    int knobW = adsrRow.getWidth() / 4;
+    {
+        juce::Slider* s[] = { &attackSlider, &decaySlider, &sustainSlider, &releaseSlider };
+        juce::Label*  l[] = { &attackLabel,  &decayLabel,  &sustainLabel,  &releaseLabel };
+        for (int i = 0; i < 4; ++i)
+        {
+            auto col = adsrRow.removeFromLeft (knobW);
+            l[i]->setBounds (col.removeFromBottom (14));
+            s[i]->setBounds (col);
+        }
+    }
+
+    area.removeFromTop (2);
+
+    // Bottom row: Pitch, Pan, Cutoff, Reso
+    auto bottomRow = area;
+    knobW = bottomRow.getWidth() / 4;
+    {
+        juce::Slider* s[] = { &pitchSlider, &panSlider, &cutoffSlider, &resoSlider };
+        juce::Label*  l[] = { &pitchLabel,  &panLabel,  &cutoffLabel,  &resoLabel };
+        for (int i = 0; i < 4; ++i)
+        {
+            auto col = bottomRow.removeFromLeft (knobW);
+            l[i]->setBounds (col.removeFromBottom (14));
+            s[i]->setBounds (col);
+        }
+    }
+}