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/GrainControlPanel.cpp

@@ -0,0 +1,83 @@
+#include "GrainControlPanel.h"
+
+GrainControlPanel::GrainControlPanel()
+{
+    titleLabel.setText ("GRAIN", juce::dontSendNotification);
+    titleLabel.setJustificationType (juce::Justification::centredLeft);
+    titleLabel.setColour (juce::Label::textColourId, InstaGrainLookAndFeel::textPrimary);
+    addAndMakeVisible (titleLabel);
+
+    setupKnob (positionKnob, posLabel, "Position", 0.0, 1.0, 0.5);
+    setupKnob (sizeKnob, sizeLabel, "Size", 10.0, 500.0, 100.0, " ms");
+    setupKnob (densityKnob, densityLabel, "Density", 1.0, 100.0, 10.0, " g/s");
+    setupKnob (pitchKnob, pitchLabel, "Pitch", -24.0, 24.0, 0.0, " st");
+    setupKnob (panKnob, panLabel, "Pan", -1.0, 1.0, 0.0);
+
+    // Root Note selector (MIDI 0-127)
+    const char* noteNames[] = { "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" };
+    for (int i = 0; i <= 127; ++i)
+    {
+        int octave = (i / 12) - 1;
+        juce::String name = juce::String (noteNames[i % 12]) + juce::String (octave);
+        rootNoteBox.addItem (name, i + 1);  // ComboBox IDs start at 1
+    }
+    rootNoteBox.setSelectedId (60 + 1);  // Default: C4
+    addAndMakeVisible (rootNoteBox);
+
+    rootNoteLabel.setText ("Root", juce::dontSendNotification);
+    rootNoteLabel.setJustificationType (juce::Justification::centred);
+    rootNoteLabel.setColour (juce::Label::textColourId, InstaGrainLookAndFeel::textSecondary);
+    addAndMakeVisible (rootNoteLabel);
+}
+
+void GrainControlPanel::setupKnob (juce::Slider& knob, juce::Label& label, const juce::String& name,
+                                    double min, double max, double def, const juce::String& suffix)
+{
+    knob.setSliderStyle (juce::Slider::RotaryHorizontalVerticalDrag);
+    knob.setTextBoxStyle (juce::Slider::TextBoxBelow, false, 60, 14);
+    knob.setRange (min, max);
+    knob.setValue (def);
+    knob.setTextValueSuffix (suffix);
+    knob.getProperties().set (InstaGrainLookAndFeel::knobTypeProperty, "orange");
+    addAndMakeVisible (knob);
+
+    label.setText (name, juce::dontSendNotification);
+    label.setJustificationType (juce::Justification::centred);
+    label.setColour (juce::Label::textColourId, InstaGrainLookAndFeel::textSecondary);
+    addAndMakeVisible (label);
+}
+
+void GrainControlPanel::resized()
+{
+    auto bounds = getLocalBounds().reduced (4);
+    titleLabel.setBounds (bounds.removeFromTop (20));
+
+    int knobW = bounds.getWidth() / 6;
+    int knobH = bounds.getHeight() - 16;
+
+    auto row = bounds.removeFromTop (knobH);
+
+    juce::Slider* knobs[] = { &positionKnob, &sizeKnob, &densityKnob, &pitchKnob, &panKnob };
+    juce::Label* labels[] = { &posLabel, &sizeLabel, &densityLabel, &pitchLabel, &panLabel };
+
+    for (int i = 0; i < 5; ++i)
+    {
+        auto col = row.removeFromLeft (knobW);
+        knobs[i]->setBounds (col.reduced (2));
+        labels[i]->setBounds (col.getX(), col.getBottom() - 2, col.getWidth(), 16);
+    }
+
+    // Root Note combo in the remaining space
+    auto rootCol = row;
+    rootNoteLabel.setBounds (rootCol.removeFromTop (14));
+    rootNoteBox.setBounds (rootCol.reduced (4, 2).removeFromTop (24));
+}
+
+void GrainControlPanel::paint (juce::Graphics& g)
+{
+    auto bounds = getLocalBounds().toFloat();
+    g.setColour (InstaGrainLookAndFeel::bgMedium.withAlpha (0.5f));
+    g.fillRoundedRectangle (bounds, 4.0f);
+    g.setColour (InstaGrainLookAndFeel::bgLight.withAlpha (0.3f));
+    g.drawRoundedRectangle (bounds, 4.0f, 1.0f);
+}