Export the wiring list without building every folio (stage D5)

The wiring list export read the project as QETProject::toXml() writes
it, which builds every folio. It now reads a document made without
building: a built folio written as saving writes it
(QETProject::folioXml(), which keeps its symbols' links to partners not
built), a folio not built copied from its XML, and what QElectroTech
computes for a wire's ends -- its symbols' labels, their last partner's
label, the terminals' names -- filled in from the symbols built and from
the project database. A symbol still waiting for a partner not built
takes its partners from the database, saved order.

136-folio .qetz, wiring list from the command line: 30.1 s with every
folio built, 4.5 s lazily, same file. tst_lazyfolios: the wiring list of
a .qet and of a .qetz as when built, building no folio. New corpus gate
(it fails on
all 6 projects tried with terminal names broken): --export-cables and
--export-wires lazily from the .qet and the .qetz = eager on 342
projects; one (forum f3386) differed until waiting symbols took their
partners from the database. ctest 96/96 eager and lazy (one earlier
run had modal_quit_regression and tst_resaveunchanged fail once each,
both passing on rerun in both modes); 342 corpus projects save the same
in all four arms.

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

sources/dataBase/projectdatabase.h

@@ -195,6 +195,8 @@ class projectDataBase : public QObject
 			/// symbols at its ends (ElementData::typeToString())
 		struct FolioWire { QString text; QString kind1; QString kind2; };
 		QList<FolioWire> wiresOnFolios(const QList<QUuid> &folios) const;
+		QString elementLabel(const QUuid &element) const;
+		QString terminalName(const QUuid &terminal, const QUuid &element) const;
 		static QVariant sequenceValue(const autonum::sequentialNumbers &sequence);
 		static autonum::sequentialNumbers sequenceFromValue(const QVariant &value);