fix(ticketManagement): 添加最低消费金额必填验证

- 为最低消费金额字段添加必填校验规则
- 完善表单验证逻辑，确保数据完整性

src/views/ticketManagement/newCoupon.vue

@@ -173,6 +173,7 @@ const rules = reactive({
     }
   ],
   minimumSpendingAmount: [
+    { required: true, message: "请输入最低消费金额" },
     {
       validator: (rule: any, value: any, callback: any) => {
         if (couponModel.value.hasMinimumSpend === 1) {