- Implement SessionManager with cookie-based authentication
- Create admin routes with login, logout, password change
- Add dashboard, models, tokens, users, and chat pages
- Implement dark theme CSS with modern design
- Add user management (create, delete users)
- Add API token management placeholders
- Session-based auth with CSRF protection
- Password hashing with argon2 fallback
- Jinja2 templates for all admin pages