生成单机模式部署docker image的时候路径报错，cd: can't cd to /xfl/third_party/curve25519

=> [ 2/11] WORKDIR /xfl 0.2s
=> [ 3/11] RUN sed -i 's#http://deb.debian.org#https://mirrors.aliyun.com#g' /etc/apt/sources.list && echo 'deb http://mirr 4596.0s
=> [ 4/11] COPY . /xfl 0.1s
=> [ 5/11] RUN cd /xfl && wget https://nginx.org/download/nginx-1.20.1.tar.gz && tar -zxvf nginx-1.20.1.tar.gz && cd ./ng 16.5s
=> [ 6/11] RUN cd /xfl/xfl-java && wget -q https://archive.apache.org/dist/maven/maven-3/3.2.5/binaries/apache-maven-3.2.5-b 659.3s
=> [ 7/11] RUN ln -s /usr/bin/python3 /usr/bin/python
> [ 8/11] RUN cd /xfl/third_party/curve25519 && python setup.py install:
#12 0.614 /bin/sh: 1: cd: can't cd to /xfl/third_party/curve25519
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executor failed running [/bin/sh -c cd /xfl/third_party/curve25519 && python setup.py install]: exit code: 2

Start with the Docker image build output at step 8/11 and inspect the repository copied into /xfl, especially the expected third_party/curve25519 path. Reproduce the build and identify why that directory is absent; done means the single-machine Docker image build reaches completion without the cd error.

Written by the indexing model from the issue text.