GUI polish: 3D metal knobs, Rajdhani font, background texture, scaling UI

- Custom Rajdhani font (Regular/Medium/Bold) embedded via BinaryData
- Background carbon fiber noise texture overlay
- 3D metal knobs with radial gradient, rim, highlight, center cap
  - Orange type (ADSR/Master/Pitch/Pan) + Dark/blue type (FX/Filter)
  - Intense glow on value arc (5 layers: outer -> hot center)
  - Intense glow on pointer (4 layers)
  - All thicknesses scale proportionally with knob pixel size
- FX panel: bordered boxes for each section with gradient background
- Pad glow: cyan multi-pass glow on selected pad
- Pad numbers: dark background badge for contrast
- Waveform display: grid lines + center reference line
- VU meter: peak hold indicator + dB scale markers
- Buttons: gradient fill + hover highlight + rounded border
- All fonts and spacing scale proportionally with window size
- Top bar: darker header with gradient
- Double-click resets knobs to default values

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

Source/MasterPanel.cpp

@@ -3,7 +3,6 @@
 
 MasterPanel::MasterPanel()
 {
-    masterTitle.setFont (juce::FontOptions (12.0f, juce::Font::bold));
     masterTitle.setColour (juce::Label::textColourId, InstaDrumsLookAndFeel::textSecondary);
     addAndMakeVisible (masterTitle);
 
@@ -21,10 +20,10 @@ void MasterPanel::setupKnob (juce::Slider& s, juce::Label& l, const juce::String
     s.setTextBoxStyle (juce::Slider::NoTextBox, false, 0, 0);
     s.setRange (min, max, step);
     s.setValue (val, juce::dontSendNotification);
+    s.setDoubleClickReturnValue (true, val);
     addAndMakeVisible (s);
 
     l.setText (name, juce::dontSendNotification);
-    l.setFont (juce::FontOptions (9.0f));
     l.setColour (juce::Label::textColourId, InstaDrumsLookAndFeel::textSecondary);
     l.setJustificationType (juce::Justification::centred);
     addAndMakeVisible (l);
@@ -41,22 +40,26 @@ void MasterPanel::paint (juce::Graphics& g)
 
 void MasterPanel::resized()
 {
-    auto area = getLocalBounds().reduced (4);
+    auto area = getLocalBounds().reduced (6);
+    float scale = (float) getHeight() / 52.0f;
+    float titleSize = std::max (12.0f, 16.0f * scale);
+    float labelSize = std::max (9.0f, 12.0f * scale);
+    int labelH = (int) (labelSize + 4);
 
-    masterTitle.setBounds (area.removeFromLeft (55).reduced (0, 2));
+    masterTitle.setFont (juce::FontOptions (titleSize, juce::Font::bold));
+    masterTitle.setBounds (area.removeFromLeft ((int) (65 * scale)).reduced (0, 2));
 
-    // VU meter on the right
-    vuMeter.setBounds (area.removeFromRight (24).reduced (0, 2));
+    vuMeter.setBounds (area.removeFromRight ((int) (28 * scale)).reduced (0, 2));
     area.removeFromRight (4);
 
-    // Knobs
     int knobW = area.getWidth() / 3;
     juce::Slider* sliders[] = { &volumeSlider, &tuneSlider, &panSlider };
     juce::Label*  labels[]  = { &volumeLabel,  &tuneLabel,  &panLabel };
     for (int i = 0; i < 3; ++i)
     {
+        labels[i]->setFont (juce::FontOptions (labelSize));
         auto col = area.removeFromLeft (knobW);
-        labels[i]->setBounds (col.removeFromBottom (12));
+        labels[i]->setBounds (col.removeFromBottom (labelH));
         sliders[i]->setBounds (col);
     }
 }