fix: 修正拖曳事件僅在目標元素上觸發，並確保左鍵拖曳有效性

| 確保即時數據為陣列，避免反轉時出現錯誤

src/directives/draggable.js

@@ -4,13 +4,16 @@ const moveModal = (elmnt) => {
     pos2 = 0,
     pos3 = 0,
     pos4 = 0;
-  document.body.addEventListener("mousedown", dragMouseDown, {
+  // 只在目標元素上監聽 mousedown，避免全域攔截
+  elmnt.addEventListener("mousedown", dragMouseDown, {
     passive: false,
   });
 
   function dragMouseDown(e) {
     console.log("dragMouseDown", e);
     e = e || window.event;
+    // 僅當左鍵拖曳才阻止預設（避免影響下拉選單等）
+    if (e.button !== 0) return;
     e.preventDefault();
     // get the mouse cursor position at startup:
     pos3 = e.clientX;

src/views/dashboard/components/DashboardElectricity.vue

@@ -56,7 +56,7 @@ const getData = async () => {
 const getRealTime = async () => {
   if (store.selectedBuilding.building_guid) {
     const res = await getRealTimeDemand(store.selectedBuilding.building_guid);
-    realTimeDemand.value = res.data.reverse();
+    realTimeDemand.value = Array.isArray(res.data) ? res.data.reverse() : [];
     updateChart();
   }
 };