refactor(editor): orgnize exports (#10709)

blocksuite/playground/apps/starter/data/synced.ts

@@ -1,4 +1,4 @@
-import { MarkdownTransformer } from '@blocksuite/affine/blocks';
+import { MarkdownTransformer } from '@blocksuite/affine/blocks/root';
 import { Text, type Workspace } from '@blocksuite/affine/store';
 
 import type { InitFn } from './utils';