v1.2.2: Live spectrum analyzer, makeup gain, drag-and-drop signal chain

- Real-time FFT spectrum analyzer drawn behind EQ curves
- Makeup gain knob (+/- 24 dB) after limiter
- Draggable signal chain panel: reorder Master Gain / Limiter / Makeup Gain
- Chain order saved/restored with DAW session
- Scaled fonts in signal chain panel

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

Source/PluginProcessor.h

@@ -40,10 +40,19 @@ public:
     void removeBand (int index);
     int getNumBands() const;
 
+    // Signal chain stages
+    enum ChainStage { MasterGain = 0, Limiter, MakeupGain, NumStages };
+    static constexpr int numChainStages = (int) NumStages;
+
     // Settings
     std::atomic<bool> bypassed { false };
     std::atomic<float> masterGainDb { 0.0f };
     std::atomic<bool> limiterEnabled { true };
+    std::atomic<float> makeupGainDb { 0.0f };  // -24 to +24 dB
+
+    // Chain order (read/write from GUI, read from audio thread)
+    std::array<ChainStage, numChainStages> getChainOrder() const;
+    void setChainOrder (const std::array<ChainStage, numChainStages>& order);
 
     void setQuality (int fftOrder);
 
@@ -58,10 +67,28 @@ private:
     juce::dsp::Convolution convolution;
     juce::dsp::Limiter<float> limiter;
 
+    // Spectrum analyzer
+    static constexpr int spectrumFFTOrder = 11;  // 2048-point FFT
+    static constexpr int spectrumFFTSize = 1 << spectrumFFTOrder;
+    juce::dsp::FFT spectrumFFT { spectrumFFTOrder };
+    juce::dsp::WindowingFunction<float> spectrumWindow { spectrumFFTSize, juce::dsp::WindowingFunction<float>::hann };
+    std::array<float, spectrumFFTSize> fifoBuffer {};
+    int fifoIndex = 0;
+    std::array<float, spectrumFFTSize * 2> fftData {};
+    std::array<float, spectrumFFTSize / 2> spectrumMagnitude {};
+    juce::SpinLock spectrumLock;
+    std::atomic<bool> spectrumReady { false };
+
+public:
+    bool getSpectrum (float* dest, int maxBins) const;
+
     double currentSampleRate = 44100.0;
     int currentBlockSize = 512;
     bool firLoaded = false;
 
+    std::array<ChainStage, numChainStages> chainOrder { MasterGain, Limiter, MakeupGain };
+    juce::SpinLock chainLock;
+
     void updateFIR();
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (InstaLPEQProcessor)