📦 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/gopd/test/index.js

@@ -0,0 +1,36 @@
+'use strict';
+
+var test = require('tape');
+var gOPD = require('../');
+
+test('gOPD', function (t) {
+	t.test('supported', { skip: !gOPD }, function (st) {
+		st.equal(typeof gOPD, 'function', 'is a function');
+
+		var obj = { x: 1 };
+		st.ok('x' in obj, 'property exists');
+
+		// @ts-expect-error TS can't figure out narrowing from `skip`
+		var desc = gOPD(obj, 'x');
+		st.deepEqual(
+			desc,
+			{
+				configurable: true,
+				enumerable: true,
+				value: 1,
+				writable: true
+			},
+			'descriptor is as expected'
+		);
+
+		st.end();
+	});
+
+	t.test('not supported', { skip: !!gOPD }, function (st) {
+		st.notOk(gOPD, 'is falsy');
+
+		st.end();
+	});
+
+	t.end();
+});