Users can authenticate against an LDAP/AD server with configurable
server URL, bind DN, search base, and user filter. Supports StartTLS
and LDAPS — plaintext is not allowed. Both Active Directory (memberOf)
and POSIX groups (memberUid) are mapped to BamBuddy groups on each
login. Auto-provisioning creates local accounts on first LDAP login.
Local admin accounts remain as fallback when LDAP is unreachable.
Password management is disabled for LDAP users.