fix: resolve all 65 pre-existing frontend test failures (318/318 passing)

- Remove duplicate vi.mock(@/api/hooks) in SettingsRoles.test.tsx that overrode forceUpdate logic
- SettingsRoles mock: use vi.hoisted for shared forceUpdateRef between useRoles and useUpdateRole
- SettingsRoles mock: use plain async functions instead of vi.fn().mockImplementation for mutations

frontend/src/__tests__/settings/SettingsUsers.test.tsx

@@ -11,6 +11,7 @@ const mockUsers = [
 ];
 
 vi.mock('@/api/hooks', () => ({
+  useRoles: () => ({ data: { items: [] }, isLoading: false }),
   useUsers: () => ({
     data: { items: mockUsers, total: 3 },
     isLoading: false,