fix(lastleg): trace return carton sources and generate scannable labels

lastleg-service/src/main/resources/openapi/overseas-business-v1.yaml

@@ -1393,6 +1393,21 @@ paths:
         - { name: overseasWarehouseId, in: query, schema: { type: string, maxLength: 128 } }
         - { name: skuCode, in: query, schema: { type: string, maxLength: 128 } }
       responses: { '200': { description: 当前客户 SKU 汇总库存分页 } }
+  /api/merchant/v1/last-leg/return-inventory/cartons:
+    get:
+      summary: 客户退货箱号分页
+      description: 需要 merchant:overseas-warehouse:return-inventory:list。客户范围仅取登录身份且精确匹配；每个实物箱一条记录，SKU 筛选使用存在性条件，不重复箱号或放大总箱数。
+      security: [{ bearerAuth: [] }]
+      parameters:
+        - { name: page, in: query, schema: { type: integer, minimum: 1, default: 1 } }
+        - { name: size, in: query, schema: { type: integer, minimum: 1, maximum: 200, default: 20 } }
+        - { name: overseasWarehouseId, in: query, schema: { type: string } }
+        - { name: skuCode, in: query, schema: { type: string } }
+        - { name: cartonMark, in: query, schema: { type: string } }
+        - { name: returnNo, in: query, schema: { type: string } }
+        - { name: status, in: query, schema: { type: string } }
+      responses:
+        '200': { description: 分页 records 每箱一行，包含 cartonMark、overseasWarehouseId、sourceBatchNo、sourceReturnNo、status、skuTypes、totalQuantity、length、width、height、weight、createdAt；total 为实际箱数 }
   /api/merchant/v1/last-leg/return-inventory/cartons/{cartonMark}:
     get:
       summary: 客户查询退货箱明细