Per-pad FX chain, animated toggles, GR meter, simplified master panel

- FX moved from master bus to per-pad processing:
  each pad has its own Filter, Distortion, EQ, Compressor, Reverb
  via DrumPad::applyPadFx() with temp buffer rendering
- FxPanel now edits the selected pad's FX parameters
- Animated toggle switches with smooth lerp transition and glow
- Per-pad compressor GR meter connected to FxPanel display
- Master panel simplified: Volume/Tune/Pan + Limiter toggle + VU meter
- Master bus chain: Vol/Pan → Output Limiter (0dB brickwall) → VU
- Pointer glow reduced to half intensity (4 layers, narrower spread)
- Smooth 8-layer arc glow with exponential opacity falloff

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Source/FxPanel.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <JuceHeader.h>
+#include "DrumPad.h"
 
 class FxPanel : public juce::Component
 {
@@ -9,37 +10,47 @@ public:
     void paint (juce::Graphics& g) override;
     void resized() override;
 
-    // FX parameter getters (for processor to read)
-    float getCompThreshold() const { return (float) compThreshSlider.getValue(); }
-    float getCompRatio()     const { return (float) compRatioSlider.getValue(); }
-    float getEqLo()          const { return (float) eqLoSlider.getValue(); }
-    float getEqMid()         const { return (float) eqMidSlider.getValue(); }
-    float getEqHi()          const { return (float) eqHiSlider.getValue(); }
-    float getDistDrive()     const { return (float) distDriveSlider.getValue(); }
-    float getDistMix()       const { return (float) distMixSlider.getValue(); }
-    float getReverbSize()    const { return (float) reverbSizeSlider.getValue(); }
-    float getReverbDecay()   const { return (float) reverbDecaySlider.getValue(); }
+    // Connect to a pad's FX params
+    void setPad (DrumPad* pad);
+    void syncToPad();   // write GUI values to pad
+    void syncFromPad(); // read pad values to GUI
+
+    // Compressor GR meter
+    void setCompGainReduction (float grDb) { compGrDb = grDb; repaint (compGrArea); }
+
+    void paintOverChildren (juce::Graphics& g) override;
 
 private:
     // Compressor
     juce::Slider compThreshSlider, compRatioSlider;
     juce::Label  compThreshLabel, compRatioLabel, compTitle;
+    juce::ToggleButton compToggle;
 
     // EQ
     juce::Slider eqLoSlider, eqMidSlider, eqHiSlider;
     juce::Label  eqLoLabel, eqMidLabel, eqHiLabel, eqTitle;
+    juce::ToggleButton eqToggle;
 
     // Distortion
     juce::Slider distDriveSlider, distMixSlider;
     juce::Label  distDriveLabel, distMixLabel, distTitle;
+    juce::ToggleButton distToggle;
 
     // Reverb
     juce::Slider reverbSizeSlider, reverbDecaySlider;
     juce::Label  reverbSizeLabel, reverbDecayLabel, reverbTitle;
+    juce::ToggleButton reverbToggle;
+
+    DrumPad* currentPad = nullptr;
+
+    float compGrDb = 0.0f;
+    bool repaintCompGr = false;
+    juce::Rectangle<int> compGrArea;  // stored from resized for paintOverChildren
 
     void setupKnob (juce::Slider& s, juce::Label& l, const juce::String& name,
                     double min, double max, double val, double step = 0.01);
     void setupTitle (juce::Label& l, const juce::String& text);
+    void setupToggle (juce::ToggleButton& t);
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (FxPanel)
 };