新增库位下拉接口及相关DTO与错误提示优化

新增 GetLocationOption 接口，完善 Controller、Service 层及 MmLocationOption DTO，实现库位下拉数据获取。修正仓库或库位不存在时的错误提示信息。

DOAN.Admin.WebApi/Controllers/MES/Material/productionMaterial/MmInventoryController.cs

@@ -110,6 +110,17 @@ namespace DOAN.Admin.WebApi.Controllers.BZFM
             return SUCCESS(response);
         }
         /// <summary>
+        /// 获取库位下拉数据
+        /// </summary>
+        /// <returns></returns>
+        [HttpPost("GetLocationOption")]
+        public IActionResult GetLocationOption()
+        {
+            var response = _MmInventoryService.GetLocationOption();
+
+            return SUCCESS(response);
+        }
+        /// <summary>
         /// 获取出/入库操作类型下拉数据
         /// </summary>
         /// <returns></returns>