📦 添加虚拟环境和启动脚本

新增:
- backend/venv/ - Python 虚拟环境
- backend/start.sh - 启动脚本（使用虚拟环境）
- backend/requirements.txt - 依赖列表
- .gitignore - 忽略虚拟环境和缓存文件

说明:
- 每个项目使用独立虚拟环境
- 避免依赖冲突
- 启动脚本自动创建和激活虚拟环境

frontend/node_modules/async-function/CHANGELOG.md

@@ -0,0 +1,16 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## v1.0.0 - 2025-01-22
+
+### Commits
+
+- Initial implementation, tests, readme, types [`8ad64e4`](https://github.com/ljharb/async-function/commit/8ad64e45668359cf032e095afcbe6ef0d291d6b4)
+- Initial commit [`36dac0d`](https://github.com/ljharb/async-function/commit/36dac0de439b8b6d7af6a246cf984b087efaaf87)
+- [meta] reformat `package.json` [`11ff004`](https://github.com/ljharb/async-function/commit/11ff0044813122c6d22e3bf360af979f7c3f7fc8)
+- first publish [`5ed020c`](https://github.com/ljharb/async-function/commit/5ed020c7852e90f280517a06e4a4d3cb1d295e40)
+- Only apps should have lockfiles [`b746134`](https://github.com/ljharb/async-function/commit/b74613407f749720b7d02b26b9fb2093a0124878)