Build errors with user-feedback example

[ucyo]

The user feedback example is not working out-of-the-box. It seems to be an import problem.

Reproduction of error

Building the following Dockerfile and running it causes an build error

FROM node:25-slim AS builder

RUN apt-get update -y && apt-get install git -y

WORKDIR /app

RUN git clone https://github.com/langfuse/langfuse-examples.git

WORKDIR /app/langfuse-examples/applications/user-feedback

RUN npm install

CMD ["npm", "run", "dev"]

Error

## Error Type
Build Error

## Error Message
Module not found: Can't resolve '@/lib/utils'

## Build Output
./components/ai-elements/branch.tsx:4:1
Module not found: Can't resolve '@/lib/utils'
  2 |
  3 | import { Button } from "@/components/ui/button";
> 4 | import { cn } from "@/lib/utils";
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  5 | import type { UIMessage } from "ai";
  6 | import { ChevronLeftIcon, ChevronRightIcon } from "lucide-react";
  7 | import type { ComponentProps, HTMLAttributes, ReactElement } from "react";

Import map: aliased to relative './lib/utils' inside of [project]/

Import traces:
  Client Component Browser:
    ./components/ai-elements/branch.tsx [Client Component Browser]
    ./app/page.tsx [Client Component Browser]
    ./app/page.tsx [Server Component]

  Client Component SSR:
    ./components/ai-elements/branch.tsx [Client Component SSR]
    ./app/page.tsx [Client Component SSR]
    ./app/page.tsx [Server Component]

https://nextjs.org/docs/messages/module-not-found

Next.js version: 16.0.1 (Turbopack)