[Files Refactor] Set primary flag when cleaning (#2880)

* Ensure single primary per object
* Set primary file during clean
* Only show migration notes for actual migrations

pkg/sqlite/gallery.go

@@ -246,6 +246,12 @@ func (qb *GalleryStore) UpdatePartial(ctx context.Context, id int, partial model
 		}
 	}
 
+	if partial.PrimaryFileID != nil {
+		if err := galleriesFilesTableMgr.setPrimary(ctx, id, *partial.PrimaryFileID); err != nil {
+			return nil, err
+		}
+	}
+
 	return qb.Find(ctx, id)
 }