feat: Add sketch mode UI tab with drawing tools

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

src/MainWindow.h

@@ -6,6 +6,8 @@
 class ViewportWidget;
 class Document;
 class Feature;
+class QTabWidget;
+class QWidget;
 
 class MainWindow : public QMainWindow
 {
@@ -20,6 +22,7 @@ private slots:
     bool save();
     bool saveAs();
     void createSketch();
+    void saveSketch();
 
 private:
     void setCurrentFile(const QString &fileName);
@@ -27,6 +30,12 @@ private:
     ViewportWidget *m_viewport;
     Document *m_document;
     QString m_currentFile;
+
+    QTabWidget *m_tabWidget;
+    QWidget *m_solidTab;
+    QWidget *m_surfaceTab;
+    QWidget *m_toolsTab;
+    QWidget *m_sketchTab;
 };
 
 #endif // MAINWINDOW_H