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/MasterPanel.cpp

@@ -10,6 +10,13 @@ MasterPanel::MasterPanel()
     setupKnob (tuneSlider,   tuneLabel,   "Tune",  -12.0, 12.0, 0.0, 0.1);
     setupKnob (panSlider,    panLabel,    "Pan",    -1.0, 1.0, 0.0, 0.01);
 
+    limiterToggle.setToggleState (true, juce::dontSendNotification);
+    limiterToggle.setButtonText ("");
+    addAndMakeVisible (limiterToggle);
+    limiterLabel.setColour (juce::Label::textColourId, InstaDrumsLookAndFeel::accent);
+    limiterLabel.setJustificationType (juce::Justification::centredLeft);
+    addAndMakeVisible (limiterLabel);
+
     addAndMakeVisible (vuMeter);
 }
 
@@ -45,13 +52,29 @@ void MasterPanel::resized()
     float titleSize = std::max (12.0f, 16.0f * scale);
     float labelSize = std::max (9.0f, 12.0f * scale);
     int labelH = (int) (labelSize + 4);
+    int toggleW = std::max (28, (int) (36 * scale));
+    int toggleH = std::max (14, (int) (16 * scale));
 
     masterTitle.setFont (juce::FontOptions (titleSize, juce::Font::bold));
     masterTitle.setBounds (area.removeFromLeft ((int) (65 * scale)).reduced (0, 2));
 
+    // VU meter on right
     vuMeter.setBounds (area.removeFromRight ((int) (28 * scale)).reduced (0, 2));
-    area.removeFromRight (4);
+    area.removeFromRight (6);
 
+    // Limiter toggle + label
+    auto limArea = area.removeFromRight ((int) (90 * scale));
+    {
+        auto center = limArea.withSizeKeepingCentre (limArea.getWidth(), toggleH + 4);
+        auto row = center;
+        limiterToggle.setBounds (row.removeFromLeft (toggleW).withSizeKeepingCentre (toggleW, toggleH));
+        limiterLabel.setFont (juce::FontOptions (std::max (10.0f, 13.0f * scale), juce::Font::bold));
+        limiterLabel.setBounds (row);
+    }
+
+    area.removeFromRight (6);
+
+    // Master knobs
     int knobW = area.getWidth() / 3;
     juce::Slider* sliders[] = { &volumeSlider, &tuneSlider, &panSlider };
     juce::Label*  labels[]  = { &volumeLabel,  &tuneLabel,  &panLabel };