- Admin users can choose to install skills to public (built-in) or custom category via UI radio selector in InstallSkillDialog
- Backend: SkillStorage.ainstall_skill_from_archive accepts target_category param; non-admin 403 on public install
- Backend: AgentStore/SkillStore add count_owned(user_id); UserRepository/LocalAuthProvider add list_users()
- Backend: GET /api/v1/auth/users endpoint (admin-only) returns all users with skill_count and agent_count
- Frontend: admin-only "用户管理" nav item in sidebar; /page/workspace/admin/users route with user table
- i18n: added sidebar.users and adminUsers section in zh-CN/en-US
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
