fixes #9234 - reduce login configuration delay by short-circuiting admin lookups and timing out unreachable parent requests.

Summary

• limit the admin lookup to a single _users document and map success responses to true
• timeout the parent domain configuration fetch at three seconds and surface failures as offline
• keep the login screen in the offline state whenever configuration checks return falsy responses

https://chatgpt.com/codex/tasks/task_e_68f29c27a30c832dabb8b0e934e0c1a0