Splits fn=admin into two independent modules: the original status
dashboard stays at fn=admin, user management moves to a new fn=usr
(IntranetController.AdminUsers.cs, fis.usr.js). Both are now reached
through a single "Administration" sidemenu dropdown (Systemüberwachung /
Benutzerverwaltung) gated by one shared fds_sys > 4 check, per ADR 0015
(supersedes 0014's "fold into one module" choice).
Also fixes the password-reset validation to check only a plain 6-char
minimum instead of silently also requiring ValidatePassword's default
2-uppercase/2-lowercase/2-digit composition, which contradicted the
"mind. 6 Zeichen" message shown to the admin.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
