feat: Add interactive sketch line drawing to viewport

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

src/ApplicationController.cpp

@@ -1,6 +1,7 @@
 #include "ApplicationController.h"
 #include "Document.h"
 #include "SketchFeature.h"
+#include "SketchLine.h"
 #include "MainWindow.h"
 
 #include <QInputDialog>
@@ -126,6 +127,13 @@ void ApplicationController::beginSketchCreation()
     }
 }
 
+void ApplicationController::addLine(const gp_Pnt& start, const gp_Pnt& end)
+{
+    if (m_activeSketch) {
+        m_activeSketch->addObject(new SketchLine(start, end));
+    }
+}
+
 void ApplicationController::endSketch()
 {
     m_activeSketch = nullptr;