feat: add projection toggle button to switch between perspective and orthographic views

src/Vtk/vtkViewport.h

@@ -73,6 +73,10 @@ public:
     void SetGridAxis(Axis axis);
     Axis GetGridAxis() const { return m_GridAxis; }
 
+    // Projection control
+    void SetParallelProjection(bool parallel);
+    bool GetParallelProjection() const;
+
 protected:
     void SetupPipeline(vtkRenderWindowInteractor* iren);