feat: reduce demo login to Verwaltung + Bürosuche only

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/auth/LoginScreen.tsx

@@ -17,12 +17,8 @@ import { useSessionStore } from '../../stores/sessionStore'
 import { UserRole } from '../../domain/enums'
 
 const DEMO_ROLES: { role: UserRole; label: string; description: string }[] = [
-  { role: UserRole.ORGANIZATION_ADMIN, label: 'Org Admin', description: 'Vollzugriff Supply + Demand + Ops' },
   { role: UserRole.PROPERTY_MANAGER, label: 'Verwaltung', description: 'Portfolio verwalten + Markt durchsuchen' },
   { role: UserRole.DEMAND_USER, label: 'Bürosuche', description: 'Nur Marktsuche — kein Portfolio' },
-  { role: UserRole.REVIEWER, label: 'Reviewer', description: 'Operations Workspace' },
-  { role: UserRole.OWNER_VIEWER, label: 'Eigentümer', description: 'Supply (eingeschränkt)' },
-  { role: UserRole.SUPER_ADMIN, label: 'Super Admin', description: 'Plattform-Administrator' },
 ]
 
 export default function LoginScreen() {