总览无持仓时仍显示灰色禁用平仓按钮，避免操作列只剩打开。

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

static/hub.js

@@ -85,11 +85,19 @@
   }
 
   function closeActionButtons(brief, instanceId, online) {
-    if (!online) return "";
     const list = (brief || []).filter(function (p) {
       return !!(p && p.inst_id);
     });
-    if (!list.length) return "";
+    if (!online) {
+      return (
+        '<button type="button" class="btn btn-close-disabled" disabled title="实例离线">平仓</button>'
+      );
+    }
+    if (!list.length) {
+      return (
+        '<button type="button" class="btn btn-close-disabled" disabled title="暂无持仓">平仓</button>'
+      );
+    }
     return list
       .slice(0, 8)
       .map(function (p) {