perf(性能优化): 优化保存快照与页面缓存

ofdgo_editor_package.go

@@ -817,7 +817,7 @@ func (e *Editor) sourceReader(ctx context.Context, progress editorProgress) (*Re
 		files = make(map[string][]byte)
 	}
 	maps.Copy(files, parts)
-	reader := &Reader{Zip: e.source.reader.Zip, files: files, encryption: e.encryption, documentIndex: e.source.reader.documentIndex, selectedVersion: e.source.reader.selectedVersion}
+	reader := &Reader{Zip: e.source.reader.Zip, files: files, encryption: e.encryption, documentIndex: e.source.reader.documentIndex, selectedVersion: e.source.reader.selectedVersion, pageContents: e.source.reader.pageContents}
 	if err := reader.initRootContext(ctx); err != nil {
 		return nil, err
 	}