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/SignalChainPanel.h

@@ -0,0 +1,46 @@
+#pragma once
+#include <JuceHeader.h>
+#include "PluginProcessor.h"
+
+class SignalChainPanel : public juce::Component
+{
+public:
+    struct Listener
+    {
+        virtual ~Listener() = default;
+        virtual void chainOrderChanged (const std::array<InstaLPEQProcessor::ChainStage, InstaLPEQProcessor::numChainStages>& order) = 0;
+    };
+
+    SignalChainPanel();
+
+    void setListener (Listener* l) { listener = l; }
+    void setOrder (const std::array<InstaLPEQProcessor::ChainStage, InstaLPEQProcessor::numChainStages>& order);
+    std::array<InstaLPEQProcessor::ChainStage, InstaLPEQProcessor::numChainStages> getOrder() const { return currentOrder; }
+
+    void paint (juce::Graphics& g) override;
+    void resized() override;
+    void mouseDown (const juce::MouseEvent& e) override;
+    void mouseDrag (const juce::MouseEvent& e) override;
+    void mouseUp (const juce::MouseEvent& e) override;
+
+private:
+    static constexpr int numBlocks = InstaLPEQProcessor::numChainStages;
+    std::array<InstaLPEQProcessor::ChainStage, numBlocks> currentOrder {
+        InstaLPEQProcessor::MasterGain,
+        InstaLPEQProcessor::Limiter,
+        InstaLPEQProcessor::MakeupGain
+    };
+
+    int draggedIndex = -1;
+    float dragOffsetX = 0.0f;
+    float dragCurrentX = 0.0f;
+
+    Listener* listener = nullptr;
+
+    juce::Rectangle<float> getBlockRect (int index) const;
+    int getBlockAtX (float x) const;
+    juce::String getStageName (InstaLPEQProcessor::ChainStage stage) const;
+    juce::Colour getStageColour (InstaLPEQProcessor::ChainStage stage) const;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (SignalChainPanel)
+};