Returns one supplier branch saved in Zuper for this provider, identified by its vendor_uid. The record is read from Zuper, not the supplier, and includes the supplier_provider_details block with the branch code, the job account used for orders and, for QXO, the owning QXO account. Payment-term settings (accounts), bank details, contacts, attachments and created_by are not returned. A branch_uid that is not saved under this provider returns 404. The provider must exist and be CONNECTED; otherwise the request fails with 404 (unknown provider) or 403 (not connected or reconnect required).