Add --export-wiring: the wiring list, headless

The wiring_list_view added by this slice was only reachable through the GUI,
which meant the one thing worth proving about it -- that it still describes
the project -- could not be checked without a person clicking. This is the
same shape as the existing --export-bom, which reads
element_nomenclature_view, and it makes the view verifiable in CI.

It also makes this slice useful on its own: a from-to wiring list is a thing
people want as a CSV, and it no longer waits on the dialog in the next slice.

There is deliberately an overlap with --export-cables, which produces the same
logical list from the document XML rather than the database. Keeping both is
the point: running them and diffing them is a direct check that the cache and
the document still agree, which nothing else in the codebase can do.

Measured on the example corpus, the two also differ in what they can actually
fill in. Rows carrying any endpoint data:

                        --export-cables    --export-wiring
  industrial.qet             0 / 671          541 / 671
  m_000.qet                  0 / 457          362 / 457
  affuteuse_250h.qet         0 / 263          197 / 263
  tremie_vibrante.qet        0 /  77           61 /  77
  tableau_domestique.qet    58 / 130          104 / 130

Both return a row per conductor; the XML-derived one leaves the component and
terminal columns empty on the older projects, and emits an unresolved "%id"
in its folio column. That is not an argument for removing it -- it carries
columns the view does not, and it is the independent second opinion -- but it
does mean the database path is the one with the data on the projects people
actually have.

The terminal-name columns come back empty on most projects. That is absent
source data, not a loss in transit: tableau_domestique.qet has no terminal
name on 457 of 457 terminals, and industrial.qet stores the "_" placeholder
on 1421 of 1790.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

sources/cli_export.cpp

@@ -70,6 +70,7 @@ const QHash<QString, QString> &exportFlags()
 		{"--export-cables", "cables"},
 		{"--export-wires", "wires"},
 		{"--export-bom", "bom"},
+		{"--export-wiring", "wiring"},
 		{"--export-nets", "nets"},
 		{"--export-links", "links"},
 		{"--info", "info"},
@@ -525,6 +526,54 @@ QHash<Element *, int> folioIndex(QETProject &project)
 	return folio;
 }
 
+/// From-to wiring list: one row per conductor, each endpoint resolved to its
+/// element label and terminal name.
+///
+/// Reads wiring_list_view out of the project database. --export-cables produces
+/// the same logical list from the document XML instead, and the two are meant
+/// to agree: running both and diffing them is a direct check that the database
+/// still describes the project, which is otherwise only observable through the
+/// GUI.
+int exportWiring(QETProject &project, const QString &output)
+{
+	// The project database is built lazily; force a (re)build before querying.
+	project.dataBase()->updateDB();
+
+	static const QStringList columns {
+		"wire_number", "from_element_label", "from_terminal",
+		"to_element_label", "to_terminal", "diagram_position", "conductor_uuid"
+	};
+
+	QSqlQuery query = project.dataBase()->newQuery(
+		"SELECT " % columns.join(", ") %
+		" FROM wiring_list_view ORDER BY diagram_position, wire_number");
+	if (!query.exec()) {
+		err << "Wiring list query failed: " << query.lastError().text() << "\n";
+		return 1;
+	}
+
+	QString csv = columns.join(";") % "\n";
+	int rows = 0;
+	while (query.next()) {
+		QStringList values;
+		for (int i = 0; i < columns.size(); ++i)
+			values << csvField(query.value(i).toString());
+		csv += values.join(";") % "\n";
+		++rows;
+	}
+
+	QFile file(output);
+	if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
+		err << "Cannot open '" << output << "' for writing.\n";
+		return 1;
+	}
+	QTextStream fout(&file);
+	fout << csv;
+	file.close();
+	out << "Exported " << rows << " conductor(s) -> " << output << "\n";
+	return 0;
+}
+
 /// Electrical nets: groups of terminals joined into one potential.
 /// Walks QET's own potential graph, so each net is a connected component
 /// of terminals across all folios. The ground truth for connectivity.
@@ -823,6 +872,8 @@ int run(const QStringList &args)
 		return exportCsv(project, format, output);
 	if (format == "bom")
 		return exportBom(project, output);
+	if (format == "wiring")
+		return exportWiring(project, output);
 	if (format == "nets")
 		return exportNets(project, output);
 	if (format == "links")

sources/cli_export.h

@@ -48,6 +48,7 @@ namespace CLIExport {
 		  qelectrotech --export-cables  <project.qet> <output.csv>
 		  qelectrotech --export-wires   <project.qet> <output.csv>
 		  qelectrotech --export-bom     <project.qet> <output.csv>
+		  qelectrotech --export-wiring  <project.qet> <output.csv>
 		  qelectrotech --export-nets    <project.qet> <output.json>
 		  qelectrotech --export-links   <project.qet> <output.csv>
 		  qelectrotech --info           <project.qet> [output.json]
@@ -60,6 +61,11 @@ namespace CLIExport {
 		cables: wiring list (one row per conductor) as CSV.
 		wires: list of distinct wire numbers as CSV.
 		bom: bill of materials (one row per element) as CSV.
+		wiring: from-to wiring list (one row per conductor) as CSV, read from
+		        the project database. Same logical list as `cables`, which
+		        reads the document XML instead; the two are meant to agree,
+		        so diffing them checks that the database still describes the
+		        project.
 		nets: electrical nets (connected-terminal groups) as JSON.
 		links: element cross-references (coil/contact) as CSV, with
 		       unresolved links flagged.