Initial release — InstaShadow mastering compressor v1.0

Dual-stage compressor (optical + VCA) with output transformer saturation.
- Port-Hamiltonian T4B opto-cell model with implicit trapezoidal integration
- Feed-forward VCA with 7 ratios, 6 attack/release presets, Dual release mode
- 3 transformer types (Nickel/Iron/Steel) with 4x oversampled waveshaping
- Analog-style needle VU meters, horizontal GR meters
- Sidechain HPF, stereo link, independent section bypass
- Full state save/restore, CI/CD for Windows/macOS/Linux

Source/OpticalPanel.cpp

@@ -0,0 +1,73 @@
+#include "OpticalPanel.h"
+
+OpticalPanel::OpticalPanel()
+{
+    titleLabel.setText ("OPTICAL", juce::dontSendNotification);
+    titleLabel.setJustificationType (juce::Justification::centred);
+    titleLabel.setColour (juce::Label::textColourId, InstaShadowLookAndFeel::textPrimary);
+    addAndMakeVisible (titleLabel);
+
+    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, 60, 14);
+        knob.setRange (min, max);
+        knob.setValue (def);
+        knob.setTextValueSuffix (suffix);
+        knob.getProperties().set (InstaShadowLookAndFeel::knobTypeProperty, type);
+        addAndMakeVisible (knob);
+
+        label.setText (name, juce::dontSendNotification);
+        label.setJustificationType (juce::Justification::centred);
+        label.setColour (juce::Label::textColourId, InstaShadowLookAndFeel::textSecondary);
+        addAndMakeVisible (label);
+    };
+
+    setupKnob (thresholdKnob, threshLabel, "Threshold", -40.0, 0.0, -20.0, "orange", " dB");
+    setupKnob (gainKnob, gainLabel, "Gain", 0.0, 20.0, 0.0, "orange", " dB");
+    setupKnob (scHpfKnob, hpfLabel, "SC HPF", 20.0, 500.0, 90.0, "dark", " Hz");
+    scHpfKnob.setSkewFactorFromMidPoint (100.0);
+
+    bypassToggle.setButtonText ("");
+    addAndMakeVisible (bypassToggle);
+    bypassLabel.setText ("Bypass", juce::dontSendNotification);
+    bypassLabel.setJustificationType (juce::Justification::centred);
+    bypassLabel.setColour (juce::Label::textColourId, InstaShadowLookAndFeel::textSecondary);
+    addAndMakeVisible (bypassLabel);
+}
+
+void OpticalPanel::resized()
+{
+    auto bounds = getLocalBounds().reduced (4);
+    titleLabel.setBounds (bounds.removeFromTop (18));
+
+    int availH = bounds.getHeight() - 22;
+    int knobH = availH / 3;
+
+    auto k1 = bounds.removeFromTop (knobH);
+    thresholdKnob.setBounds (k1.withTrimmedBottom (14).reduced (4, 0));
+    threshLabel.setBounds (k1.getX(), k1.getBottom() - 14, k1.getWidth(), 14);
+
+    auto k2 = bounds.removeFromTop (knobH);
+    gainKnob.setBounds (k2.withTrimmedBottom (14).reduced (4, 0));
+    gainLabel.setBounds (k2.getX(), k2.getBottom() - 14, k2.getWidth(), 14);
+
+    auto k3 = bounds.removeFromTop (knobH);
+    scHpfKnob.setBounds (k3.withTrimmedBottom (14).reduced (4, 0));
+    hpfLabel.setBounds (k3.getX(), k3.getBottom() - 14, k3.getWidth(), 14);
+
+    auto bpRow = bounds;
+    bypassLabel.setBounds (bpRow.removeFromLeft (bpRow.getWidth() / 2));
+    bypassToggle.setBounds (bpRow.reduced (4, 2));
+}
+
+void OpticalPanel::paint (juce::Graphics& g)
+{
+    auto bounds = getLocalBounds().toFloat();
+    g.setColour (InstaShadowLookAndFeel::bgMedium.withAlpha (0.5f));
+    g.fillRoundedRectangle (bounds, 4.0f);
+    g.setColour (InstaShadowLookAndFeel::bgLight.withAlpha (0.3f));
+    g.drawRoundedRectangle (bounds, 4.0f, 1.0f);
+}