Why: Administrators and delegated system managers need focused role, user, and permission controls with search, filters, single-role editing, and a matrix view.
Evidence: Frontend 280 tests, production build, paired UI 163 tests, and design guards passed.
Impact: Replaces the RDM role panel with Backend role authority and adds optional user profiles, unique role assignment, and explicit system-grant editing.
Refs: Focused role and permission system task 7