Write a symbol's link rows in the order it saves them, with its waiting partners

The project database's link table should say what each symbol saves:
QETZ-DB-FIRST stage 2a moves link reading and writing to it. Measured over
the corpus and 25 kinds of edit, its rows disagreed with the file for
three reasons; this fixes the one in the database:

- rows followed the order partners were built in, not the order the
  symbol saves them (11 symbols, mostly .qetz files where an edit built a
  partner's folio, with lazy folios);
- the rows were written by three pieces of code with three rules: the
  rebuild and the flush from the built partners then the waiting ones,
  the save from its own list.

Element::linksToSave() is now that one list: the order the symbol was
saved with, then partners linked since, a partner on a folio not built
included. toXml() writes it and the database's rows are written from it
(projectDataBase::insertLinkRows()), with their place in a new ord
column of the in-memory table (the .qetz file's own link table is not
touched). A built partner the project no longer has, on a removed folio,
still gets no row, as before.

The other two reasons are not here: symbols sharing a uuid (PR #1522)
and links saved to symbols on a removed folio (F113), which the save will
stop writing once it writes from the database (stage 2a-2).

QET_CHECK_LINK_ROWS=1 says at each save whether the rows are what the
symbols save, without building any folio. tst_resaveunchanged
linkRowsAfterLazyEdit moves a symbol of m_000 as a .qetz with lazy
folios: with the previous order, 2 symbols differ.

No saved byte changes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XCdg2Er2vYhB8Vwa5G7fSR

sources/dataBase/projectdatabase.h

@@ -154,6 +154,7 @@ class projectDataBase : public QObject
 		void conductorPropertiesStored(Conductor *conductor, const ConductorProperties &properties);
 		void conductorUuidChanged(Conductor *conductor, const QUuid &old_uuid);
 		QStringList conductorPropertiesMismatches() const;
+		QStringList linkRowMismatches();
 
 			//Fill the three stores from a project's document before its
 			//folios are built, then, once
@@ -253,6 +254,8 @@ class projectDataBase : public QObject
 		void populateConductorTable();
 		void populateLinkTable();
 		void flushLinks();
+		void insertLinkRows(QSqlQuery &insert, Element *element, const QSet<QUuid> &waiting);
+		QSet<QUuid> waitingSymbols() const;
 		void populateDrawingItemTables();
 		bool populateFromDocument(const QDomDocument &document, QString *why = nullptr);
 		bool writeDrawingItem(QObject *object);