refactor(设备详情): 使用计算属性转换告警计划数据类型

将直接的类型断言转换为计算属性，提高代码可读性和类型安全性

src/views/device/detail/index.vue

@@ -293,7 +293,7 @@
         v-model:open="alarmPlanVisible"
         :client-id="clientId"
         :alarm-plan-id="alarmPlanId"
-        :data="alarmPlanData as AlarmPlan"
+        :data="alarmPlanDataWithType"
         :area="{
           width: (detailState.width as number) ?? 0,
           height: (detailState.length as number) ?? 0,
@@ -734,6 +734,8 @@ interface AlarmPlanItem {
   [key: string]: unknown
 }
 const alarmPlanData = ref<AlarmPlanItem | undefined>(undefined)
+const alarmPlanDataWithType = computed(() => alarmPlanData.value as AlarmPlan)
+
 // 编辑告警计划
 const editAlarmItem = async (item: AlarmPlanItem) => {
   console.log('editAlarmItem', item)