implement debug draw mode

src/ui/GameWorldView.h

@@ -81,6 +81,7 @@ private:
     void drawBeltItems(QPainter& painter);
     void drawScrap(QPainter& painter);
     void drawShips(QPainter& painter);
+    void drawDebugSensorRanges(QPainter& painter);
     void drawBeams(QPainter& painter);
     void drawOverlays(QPainter& painter);
     void drawScreenSpace(QPainter& painter);
@@ -156,6 +157,7 @@ private:
 
     bool     m_demolishMode;
     EntityId m_demolishHoverId;
+    bool     m_debugDraw;
 
     std::vector<EntityId> m_selectedIds;
     bool                  m_boxSelecting;