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/LookAndFeel.h

@@ -26,6 +26,10 @@ public:
                                bool shouldDrawButtonAsHighlighted,
                                bool shouldDrawButtonAsDown) override;
 
+    void drawToggleButton (juce::Graphics& g, juce::ToggleButton& button,
+                           bool shouldDrawButtonAsHighlighted,
+                           bool shouldDrawButtonAsDown) override;
+
     // Custom fonts
     juce::Font getRegularFont (float height) const;
     juce::Font getMediumFont (float height) const;