user accounts: assistant warns about prev conversations when logged out

id imagine we dont want warnings like this when logged out, since the expectation is you wont have previous histories. it could instead be like info blue in that case and basically say hey if you want to track conversation history then login

Start by searching the frontend for the warning text shown in the attached screenshot and trace how logged-out state selects that message and styling. Update the logged-out case to use informational styling and explain that signing in enables conversation history, then verify the assistant behavior while logged out and logged in.

Written by the indexing model from the issue text.