Resolves the user uuids a warehouse document carries (created_by_uuid,
performed_by_uuid) into names fit for a list column.
Every document list wants the same two columns — who created it and who is
responsible for it — and each of the six lists enriches its own rows, so
without a shared step each of them would either repeat the same query or,
worse, call Auth.get_user/1 once per row. resolve/2 collects the uuids of
a whole page first and fetches them in ONE get_users_by_uuids/1 call.
A uuid with no matching user (a deleted account, a document imported from elsewhere) is not an error: it renders as a short uuid stub so the column still says "somebody", instead of blanking out and reading like "nobody".
Summary
Functions
Looks one uuid up in a resolve/2 map. nil (the field was never set)
renders as an em dash — the same "no value" mark the lists use elsewhere.
Builds a %{uuid => display name} map for a list of documents.
fields names the uuid-carrying fields to collect; the default covers the
creator/responsible pair every warehouse document schema declares. Names
come from core's User.display_name/1, so a user reads the same here as
in every other PhoenixKit admin list.