fix: Sentinel 加载 chart.js + MiniChart 未就绪回退网格

plugins/sentinel/dashboard.html

@@ -1,3 +1,4 @@
+<script src="/SenSu/static/js/chart.js?v=0705"></script>
 <div class="plugin-page-root" style="padding:16px">
   <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:12px">
     <h2 style="margin:0">🛡️ Sentinel 集群监控</h2>
@@ -246,7 +247,13 @@
 
           if (isRow) {
             var charts = _chartInstances[id];
-            if (charts && charts[0]) {
+            if (!charts) {
+              // MiniChart 未加载, 回退到网格模式
+              _layoutMode = 'grid';
+              toggleLayout();
+              return;
+            }
+            if (charts[0]) {
               charts[0].update(cpuVal);
               charts[1].update(memVal);
               charts[2].update(net.rx_bytes_sec||0);