Add milestone markers for Dandiset pages for each published version

Noticed this on https://catalystneuro.github.io/asap-access-analysis/

<img width="552" height="623" alt="Image" src="https://github.com/user-attachments/assets/4886c252-78a4-4248-8fe1-27a40eca1185" />

Think on other types of milestones