Lean endpoint returning compliance status, blockers, and per-module
sub-state (buyer, order, invoice, payment, transport, export file).
Use with If-None-Match to poll cheaply — 304 when unchanged.
OAuth 2.0 client_credentials grant via Keycloak service account.
Clients are provisioned per IntegrationOrganization in the
nt24-idp realm.
UUID of the seller trade partner (must be in caller's authorized list).