UI polish: amber theme, smooth spectrum, MIDI LED, VU tuning

- Rename section labels: COMPRESSOR → COMPRESSION, AUTO-PAN → PANNING
- Replace spectrum analyzer bars with smooth gapless filled wave
- Use gold (#c59c07) for wave/spectrum strokes and piano roll active keys
- Amber CRT-style patch LCD with dark background and gold dot-matrix text
- Add MIDI signal LED with glow between semi and scale controls
- Reduce VU meter sensitivity (5x → 1.5x) and match amber gradient theme
- Add subtle glow behind section and sub-section boxes
- Fix Compressor.h class name and PluginProcessor include to match

README.md

@@ -21,7 +21,7 @@ will work reliably, be useful in any way, or even make any sense whatsoever.
 ## Signal Flow
 
 ```
-Osc1 + Osc2 → Amp Envelope × Velocity → Filter → Drive → Distortion → Compressor → Auto-Pan → Delay → Reverb → Output
+Osc1 + Osc2 → Amp Envelope × Velocity → Filter → Drive → Distortion → Compression → Auto-Pan → Delay → Reverb → Output
 ```
 
 ## Oscillators
@@ -81,7 +81,7 @@ All effects are stereo and processed in series after the synth voice.
 - **Mix** (dry/wet): 0.0 – 1.0
 - Bypassed when amount < 0.001
 
-### Compressor
+### Compression
 
 - **Threshold**: -60 dB – 0 dB
 - **Ratio**: 1:1 – 20:1
@@ -165,7 +165,7 @@ Custom dark theme with gold accents. ~50 knobs across 9 sections.
 | FILTER ENV | Attack, Decay, Sustain, Release knobs |
 | Master | Pan, Drive, Level, PB Range knobs |
 | Distortion | Type selector, Amount, Mix knobs |
-| Compressor | Threshold, Ratio, Attack, Release, Makeup, Mix knobs |
+| Compression | Threshold, Ratio, Attack, Release, Makeup, Mix knobs |
 | Auto-Pan | Rate, Depth knobs |
 | LFO 1/2 | Rate, Depth knobs, Shape and Destination selectors |
 | Delay | Time, Feedback, Mix knobs, Ping-Pong selector, Spread knob |