PreviewItems with pagination metadata.
Search organizational units on the mex-backend as a reactive resource.
Takes a Signal<string> (rather than a plain string) so the resource
re-fetches whenever the query changes — the basis for live search-as-you-type.
Must be called from an injection context, as required by httpResource. The URL
is base-href-relative so it resolves under both the dev proxy and a deployed base
href.
Get PreviewItems by its corrosponding endpoint.