📦 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/builtin-modules/package.json

@@ -0,0 +1,44 @@
+{
+	"name": "builtin-modules",
+	"version": "3.3.0",
+	"description": "List of the Node.js builtin modules",
+	"license": "MIT",
+	"repository": "sindresorhus/builtin-modules",
+	"funding": "https://github.com/sponsors/sindresorhus",
+	"author": {
+		"name": "Sindre Sorhus",
+		"email": "sindresorhus@gmail.com",
+		"url": "https://sindresorhus.com"
+	},
+	"engines": {
+		"node": ">=6"
+	},
+	"scripts": {
+		"test": "xo && ava && tsd",
+		"make": "node make.js"
+	},
+	"files": [
+		"index.js",
+		"index.d.ts",
+		"static.js",
+		"static.d.ts",
+		"builtin-modules.json"
+	],
+	"keywords": [
+		"builtin",
+		"built-in",
+		"builtins",
+		"node",
+		"modules",
+		"core",
+		"bundled",
+		"list",
+		"array",
+		"names"
+	],
+	"devDependencies": {
+		"ava": "^1.4.1",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
+	}
+}