feat: track instance copies that use links

confirm deleations when other instances link to it

Signed-off-by: Rachel Powers <508861+Ryex@users.noreply.github.com>

launcher/InstanceList.h

@@ -154,6 +154,8 @@ public:
     QStringList mimeTypes() const override;
     QMimeData *mimeData(const QModelIndexList &indexes) const override;
 
+    QStringList getLinkedInstancesById(const QString &id) const;
+
 signals:
     void dataIsInvalid();
     void instancesChanged();