Backend (user-service):
- Add admin user management APIs (list, search, statistics, detail)
- Add pagination and filtering support for user queries
- Add JWT token authentication for admin endpoints
Frontend (admin-client):
- Add UsersPage with user list, search, filters and statistics
- Add SettingsPage with admin profile, password change, system info
- Update App.tsx routes to use new pages
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
