Search users by keyword. The keyword is matched (case-insensitive, partial) against the user ID/email in the database and against display name, contact email and login ID.

• Without page and per_page at most 10 database matches plus 10 profile matches are returned and page_info contains empty strings.
• With both parameters the result is paginated.
• LDAP-imported users are no longer searched separately (v13).
• Since v13.0.28 every user contains social_auth (linked external identities).

Permission: System admin (is_staff) whose admin role grants can_manage_user. Admin roles with a restricted permission set (e.g. audit_admin, system_admin) receive 403.