Add cable management: drawing, cores, numbering, cross-references and cable list

Cables are drawn line objects (toolbar button next to the auto
break/reconnect button, click-move-click, right click cancels), not
components. The type comes from a CSV catalog following the material
list pattern (designation, cores, core colours, editable through the
entry dialog with "Nouvelle entrée" / "Modifier l'entrée").

Each core is bound to the wire its colour label stands on, and the
cable reference is generated per core and written into the Conductor
entry via Conductor::setCableReference(label, cable uuid, slot). The
conductor entry is where it has to live because the terminal strip
plan (Klemmenplan) consumes it in the next step.

Numbering: "Cables" rule under Programmeinstellungen/Neues
Projekt/Nummerierung auto (mirrored in project properties), literal
"W" fallback without a rule, French gate dialog when no rule exists,
Nummerierung menu with the renumber dialog (preferred axis, per-folio
counter, rule and counter state written back, hand-typed names ask,
whole-project scope).

Also included: label block and under-line texts with per-text font and
alignment plus the material-list cell margins, free-core placement and
right-click removal, claim questions for wires of other cables,
multi-selection drag as one undo step, type change with confirmation,
cross-references for type "Cable" (%f-%l%c, own font, clickable links
in exported PDFs), report propagation of the cable definition,
Listes menu (table of contents, material list, terminal strip manager,
terminal generator plugin, cable list), cable list with freely
selectable columns (installation/localisation of cable, start and end,
Blatt start/end, length, used cores...), CSV export dialog with column
pick and preview in the Projekt menu, script API (addTable kind
"cable_list", exportCableList) and a unit test for the type catalog.

sources/cable/cablepropertieseditorwidget.h

@@ -0,0 +1,115 @@
+/*
+	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/>.
+*/
+#ifndef CABLEPROPERTIESEDITORWIDGET_H
+#define CABLEPROPERTIESEDITORWIDGET_H
+
+#include "cable.h"
+
+#include "../PropertiesEditor/propertieseditorwidget.h"
+
+#include <QList>
+#include <QMetaObject>
+#include <QPointer>
+
+class CablePropertiesWidget;
+class CablePart;
+class QLabel;
+class QListWidget;
+class QListWidgetItem;
+
+/**
+	@brief The cable shown in the "Propriétés de la sélection" panel.
+
+	Selecting a line of a cable used to bring up nothing at all there:
+	the panel only knew the item types it already had an editor for.
+	Now it holds the very fields the cable is filled in with -- each of
+	them with its own tick saying whether the drawing shows it -- and
+	what stands there is written back live, one undo step per edit.
+*/
+class CablePropertiesEditorWidget : public PropertiesEditorWidget
+{
+		Q_OBJECT
+
+	public:
+		explicit CablePropertiesEditorWidget(Cable *cable = nullptr,
+											 CablePart *part = nullptr,
+											 QWidget *parent = nullptr);
+
+		void setCable(Cable *cable, CablePart *part = nullptr);
+
+		void apply() override;
+		void reset() override;
+		void updateUi() override;
+		QUndoCommand *associatedUndo() const override;
+		QString title() const override;
+		bool setLiveEdit(bool live_edit) override;
+
+	private:
+			///Write what is being typed onto the cable right away
+		void applyLive();
+			///He asked for the window choosing another type for this cable
+		void changeTypeRequested();
+			///Say how many cores of this cable are wired
+		void updateInfo();
+			/**
+				List the cores which stand nowhere on the sheet yet, under
+				the count of wired ones: those are the ones he can still
+				put down, and double-clicking one puts it down straight
+				from here, on the line this panel was opened for.
+			*/
+		void updateFreeCores();
+			///He double-clicked one of those cores: give it this line
+		void placeRequested(QListWidgetItem *item);
+			/**
+				He right-clicked one of them: a small menu with the one
+				thing which can be done to a core which stands nowhere
+				-- putting it down -- for whoever does not know that a
+				double click does the same.
+				@param pos where he clicked, in list coordinates
+			*/
+		void freeCoreMenu(const QPoint &pos);
+
+	private:
+		CablePropertiesWidget *m_fields = nullptr;
+		QLabel *m_info = nullptr;
+			///The cores which stand nowhere yet, listed under the count
+		QLabel *m_free_label = nullptr;
+		QListWidget *m_free_cores = nullptr;
+		QPointer<Cable> m_cable;
+			/**
+				The line this panel was opened by, which is the one a core
+				picked here is put down on: taking a core always belongs to
+				the line whose dialog was asked for, never to the first
+				line of the cable. Null while no single line is selected,
+				and then there is nothing to put a core down on and the
+				list takes no room.
+			*/
+		QPointer<CablePart> m_part;
+			///What the panel showed before the edit: the fields which
+			///differ from it are the ones the user changed
+		CableProperties m_shown;
+			///The cable the text is being typed straight into, so that
+			///reading the cable back only skips the very field which is
+			///under the fingers of the user -- and never for another
+			///cable which has just become the selected one
+		QPointer<Cable> m_live_cable;
+		QMetaObject::Connection m_live_connection;
+		bool m_updating = false;
+};
+
+#endif // CABLEPROPERTIESEDITORWIDGET_H