feat(dashboard): real user in sidebar + sign-out; strip demo/mock hints

- Sidebar footer now shows the ACE identity (was static 'James Carter') with a
  Sign-out menu; topbar user gets a Sign-out dropdown too. Both call useAuth().logout.
- Remove all visible 'Demo:' hints from login + register and the 'Demo mode' subtitle.

src/components/portal/register-flow.tsx

@@ -404,7 +404,6 @@ function VerifyChannel({ kind, initial, country, cc, initialPhone, verified, onV
           <div style={{ marginTop: 12 }}><ResendLink seconds={60} /></div>
         </div>
       )}
-      <p className="demo-hint">Demo: any 6 digits verify; “000000” fails. Email with “full”/“bo” shows send errors.</p>
     </div>
   );
 }