Found broken `/preparation-for-study/app.comflowy.com` link. Please fix!

a girl on the grass

The issue reports a broken link at '/preparation-for-study/app.comflowy.com' but provides no context. First, locate the file containing this link, likely in an MDX documentation file. Search the repository for the broken URL path. Once found, verify the correct link destination and update it. Check for any related documentation or link guidelines in the project.

索引モデルが issue の本文から書いたものです。