💄 Enhance navigation and forms for better usability

Improve menu interactions and layout for sign up and sign in forms.

✨ Add impersonation feature for public authors

Enable admins to impersonate authors for testing and support, with
visual indicators and session management.

✨ Add email search and fix entries count default in authors table

🎨 Enhance sign up and sign in headings with icons

Add icons to the sign up and sign in headings for improved visual appeal.