Improvement and fixes to the ShipmentData API

• Estimated delivery window and source indicator — The additional-information endpoint now returns deliveryStart, deliveryEnd, and a new deliveryWindowSource field indicating which source provided the ETA (e.g., carrier event, carrier booking, or SLA/config). 
   
• ETA from delivery date references not returned — Shipments with ETA stored as delivery date references (ref kinds 110/111) returned no estimated delivery date through the API. These are now included correctly. 
   
• Search result count reflected page size instead of total — Searching by order number or barcode returned a resultsCountequal to the page size rather than the total number of matching shipments. The count is now correct.