feat: 初始化 stackingdemo 项目结构

- 创建新的 Python 项目，实现堆叠集成模型功能
- 添加 pyproject.toml 配置文件，定义项目元数据和依赖管理
- 设置主程序入口 main.py，提供基础执行框架
- 配置清华大学 PyPI 镜像源以加速依赖安装
- 项目规划包含 Ridge/XGBoost/LightGBM/MLP 与决策树的堆叠组合

main.py

@@ -0,0 +1,6 @@
+def main():
+    print("Hello from stackingdemo!")
+
+
+if __name__ == "__main__":
+    main()

pyproject.toml

@@ -0,0 +1,15 @@
+[project]
+name = "stackingdemo"
+version = "0.1.0"
+description = "Stacking Ensemble Model with Ridge/XGBoost/LightGBM/MLP + Decision Tree"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = []
+
+[tool.uv]
+python-install-mirror = "https://gh-proxy.com/https://github.com/astral-sh/python-build-standalone/releases/download/"
+
+[[tool.uv.index]]
+name = "tuna"
+url = "https://mirrors.tuna.tsinghua.edu.cn/pypi/web/simple"
+default = true