fix: POP 입고 확정 시 inbound_status를 '입고완료'로 전달

기존: inbound_status 미전달 → 백엔드 기본값 '대기'
수정: '입고완료' 명시적 전달

frontend/components/pop/hardcoded/inbound/InboundCartPage.tsx

@@ -350,6 +350,7 @@ export function InboundCartPage() {
             reference_number: item.purchase_no,
             supplier_code: item.supplier_code,
             supplier_name: item.supplier_name,
+            inbound_status: "입고완료",
             inspection_status: inspResult?.completed
               ? "검사완료"
               : item.inspection_required