docs: broken external links detected

[github-actions]

Summary

Status	Count
🔍 Total	4726
🔗 Unique	896
✅ Successful	316
⏳ Timeouts	0
🔀 Redirected	2
👻 Excluded	4367
❓ Unknown	0
🚫 Errors	1
⛔ Unsupported	42

Errors per input

Errors in ./site/sitemap.xml

• [503] https://zettascalelabs.github.io/hiroz/experimental/shm/ (at 64:15) | Rejected status code: 503 Service Unavailable

Full Github Actions output