fix: MiniChart 仅新卡片创建一次 (避免重复)

plugins/sentinel/dashboard.html

@@ -213,7 +213,8 @@
               '<div class="node-time"></div>';
           }
           grid.appendChild(card);
-          if (isRow && typeof MiniChart !== 'undefined') {
+          _cardCache[id] = card;
+          if (isRow && typeof MiniChart !== 'undefined' && !_chartInstances[id]) {
             try {
               _chartInstances[id] = [
                 new MiniChart(id+'-cpu', '#7aa2f7'),
@@ -222,7 +223,6 @@
               ];
             } catch(e) {}
           }
-          _cardCache[id] = card;
         }
 
         // 更新通用信息