Keep a coil's contacts in the order the file saved them

On opening a project, a coil and its contacts are linked in the order
the folios' items are visited. When contacts are on an earlier folio
than the coil they link first, so the coil's list followed the folio
order instead of the file's, and contacts on one folio swapped places
from run to run. Saving the same project twice could then give two
different files.

After linking, Element::initLink() now puts the linked elements back in
the order the file listed them. Elements linked but not in that list
keep their place after it.

Test: tst_resaveunchanged::savedLinkOrderKept reverses a coil's two
contacts in m_000.qet and checks a resave keeps that order; it fails
without the fix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019Wga9B92BNurDEtxxtCDxf

sources/qetgraphicsitem/element.cpp

@@ -1642,6 +1642,7 @@ void Element::initLink(QETProject *prj)
 			}
 		}
 	}
+	restoreSavedLinkOrder();
 	tmp_uuids_link.clear();
 }
 
@@ -1669,9 +1670,36 @@ void Element::initLink(const QList<Element *> &candidates)
 			}
 		}
 	}
+	restoreSavedLinkOrder();
 	tmp_uuids_link.clear();
 }
 
+/**
+	@brief Element::restoreSavedLinkOrder
+	Put connected_elements back in the order tmp_uuids_link saved them.
+	Partners link in the order the folios' items are visited, and for
+	items at the same height that order changes from run to run, so a
+	master's contacts were saved in a different order each time.
+	Linked elements missing from the saved list keep their place after it.
+*/
+void Element::restoreSavedLinkOrder()
+{
+	QList<Element *> ordered;
+	for (const auto &link_info : std::as_const(tmp_uuids_link)) {
+		for (Element *elmt : std::as_const(connected_elements)) {
+			if (elmt->uuid() == link_info.uuid && !ordered.contains(elmt)) {
+				ordered << elmt;
+				break;
+			}
+		}
+	}
+	for (Element *elmt : std::as_const(connected_elements)) {
+		if (!ordered.contains(elmt))
+			ordered << elmt;
+	}
+	connected_elements = ordered;
+}
+
 /**
  * @brief Element::linkTypeToString
  * \deprecated use instead ElementData::typeToString