增强客户编码管理功能，新增客户编码唯一性校验，确保同租户内客户编码不重复。更新相关API和前端表单验证逻辑，优化Excel导入功能以处理客户编码的有效性和唯一性。添加数据库约束以维护数据完整性。

jeecgboot-vue3/src/views/xslmes/mesXslCustomer/MesXslCustomer.api.ts

@@ -5,6 +5,7 @@ const { createConfirm } = useMessage();
 
 enum Api {
   list = '/xslmes/mesXslCustomer/list',
+  checkCustomerCode = '/xslmes/mesXslCustomer/checkCustomerCode',
   queryById = '/xslmes/mesXslCustomer/queryById',
   save = '/xslmes/mesXslCustomer/add',
   edit = '/xslmes/mesXslCustomer/edit',
@@ -22,6 +23,10 @@ export const list = (params) => defHttp.get({ url: Api.list, params });
 
 export const queryById = (params: { id: string }) => defHttp.get({ url: Api.queryById, params });
 
+/** 客户编码唯一性校验（同租户；编辑传 dataId） */
+export const checkCustomerCode = (params: { customerCode: string; dataId?: string }) =>
+  defHttp.get({ url: Api.checkCustomerCode, params });
+
 export const deleteOne = (params, handleSuccess) => {
   return defHttp.delete({ url: Api.deleteOne, params }, { joinParamsToUrl: true }).then(() => {
     handleSuccess();