Export wrapped texts to DXF line by line

A symbol text with a width (text_width) is drawn wrapped on the folio,
but the DXF export split texts on '\n' only, so it was written as one
long line, running past its box and over the drawing. The export now
writes the lines of folio texts as they are laid out
(TextLines::layoutLines(), new header-only textlines.h). Texts without
a width give the same lines as before.

Tests: tst_textlines, tst_dxfwrappedtext (fails without this change).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/dxfexport.cpp

@@ -35,6 +35,7 @@
 #include "qetgraphicsitem/independenttextitem.h"
 #include "qetgraphicsitem/qetshapeitem.h"
 #include "qetgraphicsitem/terminal.h"
+#include "textlines.h"
 
 #include <QGraphicsSimpleTextItem>
 #include <QSet>
@@ -358,7 +359,8 @@ void DxfExport::write(Diagram *diagram, int width, int height,
 		qreal y = dti->scenePos().y()
 				- ydir * fontSize * 1.8
 				- xdir * fontSize * 0.9;
-		QStringList lines = dti -> toPlainText().split('\n');
+			//As drawn: a text with a width is wrapped
+		QStringList lines = TextLines::layoutLines(dti -> document());
 		qreal offset = fontSize * 1.6;
 		foreach (QString line, lines) {
 			if (line.size() > 0 && line != "_" )