Returns the details of a single event attached to a commercial transaction.


User scoping

• OPERATOR and SUPPLIER clients only for this administration route.
  
  
  Visibility
  
• OPERATOR can access any transaction event across all suppliers.
  
• SUPPLIER can access only events of transactions linked to the authenticated supplier.
  
• If the transaction or the event is outside the caller visibility scope, return 403.
  
  
  Scope
  
• Returns one event, suitable for a UI event detail view.
  
• The resource is identified by transactionId + eventId to avoid cross-transaction event access.
  
  
  Notes
  
• Some fields can be identical across all events of the same transaction, but are still returned for traceability.