Add %T, the target folio's title, to report and cross reference formulas

A folio report could name the folio it points to by position (%f), folio
number (%F), installation (%M) and location (%LM), but not by its title.
EPLAN and other tools print references like "+UV1/1 Versorgung UG/EG.0",
which with %T is the formula "+%LM/%F %T.%c".

- FormulaContext carries the folio title, filled from the title block.
- %T is replaced on its own only, not as the start of a longer word.
- A report whose formula uses %T follows the target folio's title block
  (BorderTitleBlock::informationChanged), as %F already follows its
  folio number.
- The report and cross reference property pages list %T.

tst_reportfoliotitle checks the replacement, that %total and title
block variables keep their values, and an empty title.

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

tests/qttest/CMakeLists.txt

@@ -278,6 +278,9 @@ target_compile_definitions(tst_multielementinfo PRIVATE
 # collection paths just chosen, not the ones they replace.
 qet_add_app_test(tst_assistantinfopaths tst_assistantinfopaths.cpp)
 
+# %T in a report or cross reference formula is the target folio's title.
+qet_add_app_test(tst_reportfoliotitle tst_reportfoliotitle.cpp)
+
 # Escape during a picture's resize, rotate or pivot drag puts it back, keeps
 # it selected and records no undo step (#1414); the key goes to the view.
 qet_add_app_test(tst_imagehandleescape tst_imagehandleescape.cpp)

tests/qttest/tst_reportfoliotitle.cpp

@@ -0,0 +1,80 @@
+/*
+	Copyright 2006-2026 The QElectroTech Team
+	This file is part of QElectroTech.
+
+	QElectroTech is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 2 of the License, or
+	(at your option) any later version.
+
+	QElectroTech is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "qetapptest.h"
+#include "autoNum/assignvariables.h"
+
+#include <QStandardPaths>
+
+/**
+	%T in a folio report or cross reference formula is the title of the
+	folio the reference points to, so a reference can read like the ones
+	EPLAN prints: "+UV1/1 Versorgung UG/EG.0". %total and the title block
+	and project variables (lower case only) keep their own values.
+*/
+class tst_reportfoliotitle : public QObject
+{
+	Q_OBJECT
+
+	static QString label(const QString &formula, const autonum::FormulaContext &c)
+	{
+		autonum::sequentialNumbers seq;
+		return autonum::AssignVariables::formulaToLabel(formula, seq, c);
+	}
+
+	static autonum::FormulaContext context()
+	{
+		autonum::FormulaContext c;
+		c.folio = QStringLiteral("1");
+		c.folio_title = QStringLiteral("Versorgung UG/EG");
+		c.folio_index = 2;
+		c.folio_total = 23;
+		c.locmach = QStringLiteral("UV1");
+		return c;
+	}
+
+private slots:
+	void titleIsReplaced()
+	{
+		const QString result = label(QStringLiteral("+%LM/%F %T"), context());
+		QCOMPARE(result, QStringLiteral("+UV1/1 Versorgung UG/EG"));
+	}
+
+	void otherVariablesKeepTheirValue()
+	{
+		autonum::FormulaContext c = context();
+		c.title_block_fields.addValue(QStringLiteral("typ"), QStringLiteral("SH363N"));
+		const QString result = label(QStringLiteral("%T / %total / %typ / %{typ}"), c);
+		QCOMPARE(result, QStringLiteral("Versorgung UG/EG / 23 / SH363N / SH363N"));
+	}
+
+	void emptyTitleLeavesNothing()
+	{
+		autonum::FormulaContext c = context();
+		c.folio_title.clear();
+		const QString result = label(QStringLiteral("%F%T"), c);
+		QCOMPARE(result, QStringLiteral("1"));
+	}
+};
+
+int main(int argc, char **argv)
+{
+	QStandardPaths::setTestModeEnabled(true);
+	return QetAppTest::run<tst_reportfoliotitle>(argc, argv);
+}
+
+#include "tst_reportfoliotitle.moc"