Steps to reproduce the issue:
With #5256, sharing assistant threads to unregistered users became possible. However, currently, after some change, it is not possible to access assistant threads without signin in.
- Attempt to access the following thread when not signed in to Kagi:
https://kagi.com/assistant/08aab2bf-4d14-46f1-b482-0f285acd49f2
- You will either be presented with the assistant window without any content (the tab title is still correct):

or
a login screen

Expected behavior:
Shared assistant threads should be accessible even when not signed in.