Two related problems with the default login authentication method.
- **Env var ignored:** the stored setting was only ever seeded as `password` and
`DEFAULT_AUTHENTICATION_METHOD` was never applied, so operators setting it (e.g. Kubernetes/Helm
`DEFAULT_AUTHENTICATION_METHOD: ldap`) saw no effect. Startup now applies the env var
authoritatively: it seeds the value on a fresh install and, on existing installs, keeps the
stored `defaultAuthenticationMethod` in sync with the env var on every boot (the operator's env
is the source of truth), so the method can be configured entirely by env without the Admin Panel.
The value is normalized (trimmed + lower-cased), so `DEFAULT_AUTHENTICATION_METHOD=LDAP` works.
- **Layout save hanging / not persisting:** the authentication-method `<select>` is populated by an
async `Meteor.call`, so clicking **Admin Panel > Layout > Save** before it loaded sent an empty
value for the **required** `defaultAuthenticationMethod` field, which silently failed validation —
the save looked stuck and nothing changed. The save now falls back to the currently stored method
when the select is empty, so a real value is never overwritten by `''`.
Both paths share one pure helper (`resolveDefaultAuthenticationMethod`) that never resolves to an
empty string.
Thanks to joe-speedboat and xet7 !
Fixes#5879
