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/EffectsPanel.cpp

@@ -0,0 +1,93 @@
+#include "EffectsPanel.h"
+
+EffectsPanel::EffectsPanel()
+{
+    titleLabel.setText ("FILTER / REVERB", juce::dontSendNotification);
+    titleLabel.setJustificationType (juce::Justification::centredLeft);
+    titleLabel.setColour (juce::Label::textColourId, InstaGrainLookAndFeel::textPrimary);
+    addAndMakeVisible (titleLabel);
+
+    filterTypeBox.addItem ("LP", 1);
+    filterTypeBox.addItem ("HP", 2);
+    filterTypeBox.addItem ("BP", 3);
+    filterTypeBox.setSelectedId (1);
+    addAndMakeVisible (filterTypeBox);
+
+    filterLabel.setText ("Type", juce::dontSendNotification);
+    filterLabel.setJustificationType (juce::Justification::centred);
+    filterLabel.setColour (juce::Label::textColourId, InstaGrainLookAndFeel::textSecondary);
+    addAndMakeVisible (filterLabel);
+
+    auto setupKnob = [this] (juce::Slider& knob, juce::Label& label, const juce::String& name,
+                              double min, double max, double def, const juce::String& type,
+                              const juce::String& suffix = "")
+    {
+        knob.setSliderStyle (juce::Slider::RotaryHorizontalVerticalDrag);
+        knob.setTextBoxStyle (juce::Slider::TextBoxBelow, false, 55, 14);
+        knob.setRange (min, max);
+        knob.setValue (def);
+        knob.setTextValueSuffix (suffix);
+        knob.getProperties().set (InstaGrainLookAndFeel::knobTypeProperty, type);
+        addAndMakeVisible (knob);
+
+        label.setText (name, juce::dontSendNotification);
+        label.setJustificationType (juce::Justification::centred);
+        label.setColour (juce::Label::textColourId, InstaGrainLookAndFeel::textSecondary);
+        addAndMakeVisible (label);
+    };
+
+    setupKnob (cutoffKnob, cutoffLabel, "Cutoff", 20.0, 20000.0, 20000.0, "orange", " Hz");
+    cutoffKnob.setSkewFactorFromMidPoint (1000.0);
+
+    setupKnob (resoKnob, resoLabel, "Reso", 0.1, 10.0, 0.707, "dark");
+    resoKnob.setSkewFactorFromMidPoint (1.5);
+
+    setupKnob (reverbSizeKnob, revSizeLabel, "Rev Size", 0.0, 1.0, 0.0, "dark");
+    setupKnob (reverbDecayKnob, revDecayLabel, "Rev Decay", 0.0, 1.0, 0.0, "dark");
+}
+
+void EffectsPanel::resized()
+{
+    auto bounds = getLocalBounds().reduced (4);
+    titleLabel.setBounds (bounds.removeFromTop (20));
+
+    int colW = bounds.getWidth() / 5;
+
+    // Filter type combo
+    auto typeCol = bounds.removeFromLeft (colW);
+    filterLabel.setBounds (typeCol.removeFromTop (14));
+    filterTypeBox.setBounds (typeCol.reduced (4, 2).removeFromTop (24));
+
+    // Cutoff
+    auto cutCol = bounds.removeFromLeft (colW);
+    auto cutKnobArea = cutCol.withTrimmedBottom (16);
+    cutoffKnob.setBounds (cutKnobArea.reduced (2));
+    cutoffLabel.setBounds (cutCol.getX(), cutKnobArea.getBottom() - 2, cutCol.getWidth(), 16);
+
+    // Reso
+    auto resCol = bounds.removeFromLeft (colW);
+    auto resKnobArea = resCol.withTrimmedBottom (16);
+    resoKnob.setBounds (resKnobArea.reduced (2));
+    resoLabel.setBounds (resCol.getX(), resKnobArea.getBottom() - 2, resCol.getWidth(), 16);
+
+    // Reverb Size
+    auto rsCol = bounds.removeFromLeft (colW);
+    auto rsKnobArea = rsCol.withTrimmedBottom (16);
+    reverbSizeKnob.setBounds (rsKnobArea.reduced (2));
+    revSizeLabel.setBounds (rsCol.getX(), rsKnobArea.getBottom() - 2, rsCol.getWidth(), 16);
+
+    // Reverb Decay
+    auto rdCol = bounds;
+    auto rdKnobArea = rdCol.withTrimmedBottom (16);
+    reverbDecayKnob.setBounds (rdKnobArea.reduced (2));
+    revDecayLabel.setBounds (rdCol.getX(), rdKnobArea.getBottom() - 2, rdCol.getWidth(), 16);
+}
+
+void EffectsPanel::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);
+}