fix: 구매입고 전체 프로세스 완성 (E2E 16/16 통과)

- backend: inventory_stock INSERT 시 id 누락 버그 수정
- frontend: 거래처 API supplier_mng으로 수정
- frontend: cart_items 실제 컬럼 구조 맞춤
- frontend: InboundCart 확정 로직 PC와 동일하게 정렬
- 검증: 발주→장바구니→입고등록→재고증가→발주상태변경 전체 확인

backend-node/src/controllers/receivingController.ts

@@ -246,10 +246,10 @@ export async function create(req: AuthenticatedRequest, res: Response) {
         } else {
           await client.query(
             `INSERT INTO inventory_stock (
-              company_code, item_code, warehouse_code, location_code,
+              id, company_code, item_code, warehouse_code, location_code,
               current_qty, safety_qty, last_in_date,
               created_date, updated_date, writer
-            ) VALUES ($1, $2, $3, $4, $5, '0', NOW(), NOW(), NOW(), $6)`,
+            ) VALUES (gen_random_uuid()::text, $1, $2, $3, $4, $5, '0', NOW(), NOW(), NOW(), $6)`,
             [companyCode, itemCode, whCode, locCode, String(inQty), userId]
           );
         }