fix: use require_identity for quota API to allow all authenticated users

feat: add /api/accounts/quota endpoint for regular users to view quota

Add complete Codex account export

fix auth user duplicate name response

Improve error messages and ensure unique user key names

Improve user key management with editing capabilities and validation

Add registration runner UI

feat(auth): 增加 admin/user 密钥角色与访问控制

重构后端服务，增加文本生成模型