Align instance dashboard with hub snapshot+SSE pattern.

Background poll builds a memory snapshot; the page reads snapshot and refreshes on SSE instead of hitting heavy exchange APIs on each load.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/common/static/instance_live.js

@@ -30,9 +30,7 @@
     if (tab === "options" && global.OptionsPanelLive && typeof global.OptionsPanelLive.refreshSoft === "function") {
       global.OptionsPanelLive.refreshSoft(options);
     }
-    if (tab === "dashboard" && global.InstanceDashboard && typeof global.InstanceDashboard.refreshSoft === "function") {
-      global.InstanceDashboard.refreshSoft(options);
-    }
+    // 数据看板自有 SSE + 快照,不跟 embed live tick 重拉.
   }
 
   function scheduleRefresh(opts) {