fix(theme): show toggle on standalone embed shell, not only hub iframe

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

lib/common/static/instance_theme.js

@@ -11,12 +11,6 @@
   }
 
   function isHubLinked() {
-    try {
-      const p = new URLSearchParams(location.search);
-      if (p.get("embed") === "1") return true;
-      const ht = p.get("hub_theme");
-      if (ht === "light" || ht === "dark") return true;
-    } catch (_) {}
     try {
       if (window.self !== window.top) return true;
     } catch (_) {