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>

CMakeLists.txt

@@ -20,6 +20,12 @@ juce_add_plugin(InstaDrums
 
 juce_generate_juce_header(InstaDrums)
 
+juce_add_binary_data(InstaDrumsData SOURCES
+    Resources/Rajdhani-Regular.ttf
+    Resources/Rajdhani-Medium.ttf
+    Resources/Rajdhani-Bold.ttf
+)
+
 target_sources(InstaDrums
     PRIVATE
         Source/PluginProcessor.cpp
@@ -42,6 +48,7 @@ target_compile_definitions(InstaDrums
 
 target_link_libraries(InstaDrums
     PRIVATE
+        InstaDrumsData
         juce::juce_audio_basics
         juce::juce_audio_devices
         juce::juce_audio_formats