fix(images): allow capability preview reads through the access proxy

proxy.ts

@@ -826,6 +826,15 @@ export async function proxy(request: NextRequest, event: NextFetchEvent) {
     return NextResponse.next();
   }
 
+  // Generated inline previews use an unguessable image key, like signed provider URLs.
+  // Reference-image services need to read the image before background storage finishes.
+  if (
+    (request.method === "GET" || request.method === "HEAD") &&
+    /^\/api\/generated-image-preview\/[a-f0-9]{64}$/.test(pathname)
+  ) {
+    return NextResponse.next();
+  }
+
   // 允许匿名访问新版首页灵感数据
   if (pathname === "/api/featured" || pathname.startsWith("/api/featured/")) {
     return NextResponse.next();