FORUM Sign-on and DNS for Nick

In the FORUM Document, section 4 describes Single Sign-on and DNS that is intended for Nick: https://docs.google.com/document/d/17MfdCFuAqyybD5S-VkC7DSunrugWi2rsTa9Zdmn8ffA/edit?tab=t.0#heading=h.fv537je6uiz2

Here is the introduction to Section 4:

The registration model, single sign-on, DNS, permissions, email, and Mailchimp relationship are on the critical path. They should be treated as one connected system rather than as unrelated technical tasks. The sequence matters: define who may join and where identity is managed; configure authentication; establish the final domain; then retest every login, logout, invitation, notification, and callback on that domain.

Anticipated domain: forum.zakros.com