feat: Render active sketch tool icon at cursor position

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

src/ViewportWidget.h

@@ -8,7 +8,9 @@
 #include <QVector3D>
 #include <QRect>
 #include <gp_Pnt.hxx>
+#include <QMap>
 
+class QSvgRenderer;
 class ViewCube;
 class SketchGrid;
 class Document;
@@ -88,6 +90,8 @@ private:
     gp_Pnt m_firstLinePoint;
     QPoint m_currentMousePos;
 
+    QMap<int, QSvgRenderer*> m_toolIcons;
+
     float m_xRot = 35.264f * 16.0f; // Default to isometric view
     float m_yRot = -45.0f * 16.0f;    // Default to isometric view
     float m_zoom = -5.0f;