Create Users

Create many Auth0 users in one organization.

Requires editor on the members-users module instance (POST maps to editor). Each email uses the same native Auth0 flow as POST /users. Per-email failures (duplicates, rejected addresses) are returned so one bad address does not abort the rest of the batch.

When groupId / groupIds are provided every created user is added to those groups; group validation happens once before any Auth0 writes.