Replace the stale Basic-Auth picture with the post-#523 model:
AuthSessionController + AuthService (the new auth/ package), Spring Session
JDBC (spring_session*, 8h idle timeout, fa_session cookie), and the
ChangeSessionIdAuthenticationStrategy bean used by login to defend against
session fixation. Addresses PR #612 / Markus M3.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>