refactor: Implement Rectangle tool with snapping and dimensions

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

src/SketchRectangle.h

@@ -0,0 +1,26 @@
+#ifndef SKETCHRECTANGLE_H
+#define SKETCHRECTANGLE_H
+
+#include "SketchObject.h"
+#include <gp_Pnt.hxx>
+
+class SketchRectangle : public SketchObject
+{
+public:
+    SketchRectangle();
+    SketchRectangle(const gp_Pnt& corner1, const gp_Pnt& corner2);
+
+    ObjectType type() const override;
+
+    void read(const QJsonObject& json) override;
+    void write(QJsonObject& json) const override;
+
+    const gp_Pnt& corner1() const;
+    const gp_Pnt& corner2() const;
+
+private:
+    gp_Pnt m_corner1;
+    gp_Pnt m_corner2;
+};
+
+#endif // SKETCHRECTANGLE_H