fix: Scale view cube size by device pixel ratio

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

src/ViewCube.cpp

@@ -1,8 +1,10 @@
 #include "ViewCube.h"
+#include <QGuiApplication>
 #include <QPainter>
 #include <QFont>
 #include <QOpenGLShaderProgram>
 #include <QOpenGLTexture>
+#include <QScreen>
 #include <QVector>
 
 ViewCube::ViewCube()
@@ -34,7 +36,7 @@ void ViewCube::initializeGL()
 
 void ViewCube::paintGL(QOpenGLShaderProgram* simpleShader, int simpleShaderColorLoc, const QMatrix4x4& viewMatrix, int width, int height)
 {
-    int viewCubeSize = 150;
+    int viewCubeSize = 150 * QGuiApplication::primaryScreen()->devicePixelRatio();
     glViewport(width - viewCubeSize, height - viewCubeSize, viewCubeSize, viewCubeSize);
     glClear(GL_DEPTH_BUFFER_BIT);