Tests cover:
- Anonymous reply creates UserSurrogate
- Anonymous reply with no name defaults to 'Anonymous'
- Regular namespace still requires email
- Anonymous comments are marked as verified
- Namespace settings toggle for allow_anonymous
When enabled, commenters can post with just a display name (no email required).
Comments are attached to UserSurrogate instead of User.
Trade-offs for anonymous commenters:
- No email notifications for replies
- Cannot edit their comments
- Cannot log in to manage comments
- No cross-site identity
Works with existing moderation (hide_unless_approved) - anonymous
comments are never auto-approved when moderation is enabled.
