refactor: 归档旧代码，保留新框架结构

归档内容：
- core/ (数据源、因子计算、通用工具) → archive/legacy_core/
- strategies/rotation/engine.py, portfolio.py, report.py → archive/legacy_core/
- scripts/ (run_rotation, daily_scheduler) → archive/legacy_scripts/
- examples/ → archive/legacy_examples/
- tests/ (实验、对比测试) → archive/legacy_tests/
- 单独文件 (fetch_*.py, 动量.py, 全球市场.py等) → archive/single_files/

保留新结构：
- framework/ (抽象接口)
- strategies/shared/ (定制组件)
- strategies/rotation/strategy.py (新策略)
- 外层配置: .env, .dockerignore, build-and-push.sh, hk_ecs.pem, README.md, requirements.txt
- Docker相关: Dockerfile, Dockerfile_base, docker-compose.yml

更新README反映新框架架构

archive/single_files/Dockerfile.flask

@@ -0,0 +1,38 @@
+# Flask API 服务 Dockerfile
+# =========================
+# 用于构建 Universal Data Fetcher API 服务的 Docker 镜像
+
+FROM index-base:latest
+
+# 设置工作目录
+WORKDIR /app
+
+# 复制依赖文件
+COPY requirements.txt .
+
+# 安装依赖
+RUN uv pip install --system -r requirements.txt
+
+# 仅复制除 data 目录外的应用代码
+COPY . .
+
+# 创建日志目录
+RUN mkdir -p /app/logs
+
+# 设置时区为上海
+ENV TZ=Asia/Shanghai
+
+# 暴露 Flask 服务端口
+EXPOSE 5000
+
+# 设置环境变量默认值
+ENV FLASK_APP=core/datasource/flask_server.py
+ENV FLASK_ENV=production
+ENV PYTHONUNBUFFERED=1
+
+# 健康检查
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD python -c "import requests; requests.get('http://localhost:5000/health')" || exit 1
+
+# 启动 Flask 服务
+CMD ["python", "core/datasource/flask_server.py", "--host", "0.0.0.0", "--port", "5000"]