fix: load material previews from originals

components/agents/AgentWorkflowMaterialPicker.tsx

@@ -75,16 +75,14 @@ const MaterialImageCard = memo(function MaterialImageCard({
   onToggle: (imageId: string) => void;
 }) {
   const isPlaceholder = !String(image.imageUrl || "").trim();
-  const previewUrl = String(image.previewUrl || "").trim();
-  const displayImageUrl = previewUrl || String(image.imageUrl || "").trim();
-  const fallbackImageUrl = previewUrl ? String(image.imageUrl || "").trim() : null;
+  const displayImageUrl = String(image.imageUrl || "").trim();
   const [imageStatus, setImageStatus] = useState<"loading" | "loaded" | "error">(
     isPlaceholder ? "loaded" : "loading"
   );
 
   useEffect(() => {
     setImageStatus(isPlaceholder ? "loaded" : "loading");
-  }, [displayImageUrl, fallbackImageUrl, isPlaceholder]);
+  }, [displayImageUrl, isPlaceholder]);
 
   return (
     <button
@@ -121,15 +119,12 @@ const MaterialImageCard = memo(function MaterialImageCard({
         ) : (
           <AgentPreviewImage
             src={displayImageUrl}
-            fallbackSrc={fallbackImageUrl}
             alt={image.label}
             className={cn(
               "h-full w-full object-contain transition-opacity duration-300",
               imageStatus === "loaded" ? "opacity-100" : "opacity-0"
             )}
-            delivery="proxy"
             eager
-            fallbackToOriginal={false}
             previewWidth={480}
             previewQuality={74}
             onError={() => {
@@ -146,12 +141,12 @@ const MaterialImageCard = memo(function MaterialImageCard({
               <Loader2 className="h-6 w-6 animate-spin text-emerald-200/80" />
             )}
             <div className="text-xs font-medium">
-              {imageStatus === "error" ? "预览暂不可用" : "正在加载预览"}
+              {imageStatus === "error" ? "原图暂不可用" : "正在加载原图"}
             </div>
             <div className="max-w-[180px] text-[11px] leading-5 text-white/45">
               {imageStatus === "error"
-                ? "原图地址仍可用于后续生成，可先选中或稍后重试。"
-                : "已命中素材，正在拉取缩略预览。"}
+                ? "原图地址返回异常，可先稍后重试或联系素材服务检查。"
+                : "已命中素材，正在直接拉取原图。"}
             </div>
           </div>
         ) : null}