Move scroll buttons to title bar, add build info status bar

- Replace broken bottom waveform scroll buttons with title bar < > buttons
- Add scrollLeft()/scrollRight() methods to WaveformDisplay
- Add status bar showing git branch, commit, dirty state, and build timestamp
- Inject git version info via CMake at configure time
- Enable COPY_PLUGIN_AFTER_BUILD
- Increase baseHeight by 20px for status bar

Source/WaveformDisplay.h

@@ -34,6 +34,8 @@ public:
     void zoomIn();
     void zoomOut();
     void zoomReset();
+    void scrollLeft();
+    void scrollRight();
 
     int xToSample(int x) const;
     int sampleToX(int sample) const;
@@ -63,10 +65,7 @@ private:
     std::function<void(int)> onKeyClick;
 
     juce::ScrollBar hScrollBar { false };
-    juce::TextButton scrollLeftBtn { "<" };
-    juce::TextButton scrollRightBtn { ">" };
     bool updatingScroll = false;
-    static constexpr int scrollBtnWidth = 16;
 
     juce::AudioBuffer<float> overviewBuffer;
     bool overviewDirty = true;