Auto-generate status pages from tags

**Is your feature request related to a problem? Please describe.**
I often find myself creating status pages of monitors that I have already marked with a tag.

**Describe the solution you'd like**
There should be an option where you can have a status page synced with a tag, so that by tagging a monitor it is automatically added to the status page.

Look for status page and tag management code, likely in internal handlers or services. Understand how monitors are tagged and how status pages are currently built. The feature needs to sync tag additions/removals to status page membership, requiring changes to data models and update logic. Check for existing API endpoints for tags and status pages to see where to add the sync option.

索引モデルが issue の本文から書いたものです。