feat: update Dockerfile to set custom pip index URL and install Jupyter Lab with libraries

Dockerfile

@@ -2,7 +2,8 @@
 FROM pytorch/pytorch:latest
 
 # 安装 Jupyter Lab 和常用库
-RUN pip install --upgrade pip && \
+RUN pip config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple && \
+    pip install --upgrade pip && \
     pip install jupyterlab matplotlib pandas seaborn
 
 # 设置默认工作目录