Add wiring_list_view: from-to wiring list over the conductor tables

Slice 3 of discussion #503, on top of slice 2 (#628). One row per
conductor, each endpoint resolved to its element label and terminal
name -- the `F1:4 -> M200:U1` shape from the original prototype.

The view deviates from the SQL sketched in the discussion in two ways,
both because the sketched version silently loses wires:

- **No join to the `element` table.** A terminal row already carries its
  `element_uuid`, so joining `element` back just to read the same uuid
  adds nothing. Worse, it filters: `populateElementTable()` only inserts
  elements matching `Simple|Terminal|Master|Thumbnail`, so `Slave`
  elements (relay contacts and the like -- extremely common at the end
  of a wire) and report elements are simply absent from that table after
  a project load, and an inner join through it drops their conductors.
- **`element_info` is LEFT joined** for the same reason. A wire whose
  endpoint element has no info row still belongs in a wiring list; it
  comes back with an empty label rather than vanishing. Losing a wire
  from a wiring list is a worse failure than showing one with a blank
  end.

Note this only bites after a save/reload. The incremental `addElement()`
path does not apply the type filter, so a slave element placed live is
present in `element`/`element_info` and an inner join looks fine -- it
is the bulk repopulate on project load that drops it. Testing only the
live-editing path would have missed this entirely.

Measured, comparing this view against an inner-join-through-element
variant built from the same tables in the same session:

| project | conductors | wiring_list_view | inner-join variant |
|---|---|---|---|
| Polonez MR'89 wiring diagram | 280 | 280 | 280 |
| two slave contacts, after save+reload | 1 | **1** | **0** |

Polonez happens to have no slave elements at conductor ends, so both
agree there and the problem is invisible. The second case is the
minimal reproduction: place two "Simple contact" elements
(`link_type="slave"`) so autoconnect wires them, save, reload -- the
sketched view returns zero rows for a project that plainly has a wire
in it.

Acceptance criterion held throughout: `wiring_list_view` row count
equals `conductor` row count, i.e. the view itself drops nothing.
Conductors already excluded upstream (legacy terminals without uuids,
see #628) stay excluded; that remains the only thing missing from the
list, and is what slice 4 should surface a count for.

sources/dataBase/projectdatabase.h

@@ -77,6 +77,7 @@ class projectDataBase : public QObject
 		bool createDataBase();
 		void createElementNomenclatureView();
 		void createSummaryView();
+		void createWiringListView();
 		void populateDiagramTable();
 		void populateElementTable();
 		void populateElementInfoTable();