fix: dismiss HiCAD loading state reliably

components/ai-cad/zoo-design-studio-frame.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { AlertTriangle, RefreshCw } from "lucide-react";
-import { useState } from "react";
+import { useEffect, useRef, useState } from "react";
 
 type ZooDesignStudioFrameProps = {
   isReady: boolean;
@@ -15,6 +15,30 @@ export function ZooDesignStudioFrame({
   src,
 }: ZooDesignStudioFrameProps) {
   const [loaded, setLoaded] = useState(false);
+  const iframeRef = useRef<HTMLIFrameElement>(null);
+
+  useEffect(() => {
+    if (!isReady) {
+      return;
+    }
+
+    const iframe = iframeRef.current;
+    if (!iframe) {
+      return;
+    }
+
+    const markLoaded = () => setLoaded(true);
+    iframe.addEventListener("load", markLoaded);
+    try {
+      if (iframe.contentDocument?.readyState === "complete") {
+        markLoaded();
+      }
+    } catch {
+      // The regular load event remains the fallback if access is unavailable.
+    }
+
+    return () => iframe.removeEventListener("load", markLoaded);
+  }, [isReady, src]);
 
   if (!isReady) {
     return (
@@ -54,6 +78,7 @@ export function ZooDesignStudioFrame({
         allow="clipboard-read; clipboard-write; fullscreen; gamepad; pointer-lock; web-share; xr-spatial-tracking"
         className="h-full w-full border-0"
         onLoad={() => setLoaded(true)}
+        ref={iframeRef}
         referrerPolicy="strict-origin-when-cross-origin"
         sandbox="allow-downloads allow-forms allow-modals allow-pointer-lock allow-popups allow-presentation allow-same-origin allow-scripts"
         src={src}