feat: support leaf bundles for blog posts, refactor header images

content/blog/2023-09-seafile-mirror.md

@@ -7,8 +7,9 @@ tags:
   - python
   - server
   - tools
-headerimage: /blog/library.jpg
-headercredits: Wouldn't it be a shame if your library were to be destroyed?
+headerimage:
+  src: /blog/library.jpg
+  text: Wouldn't it be a shame if your library were to be destroyed?
 ---
 
 I have been using [Seafile](https://www.seafile.com/) for years to host and