📦 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/webpack/lib/serialization/AggregateErrorSerializer.js

@@ -0,0 +1,41 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+*/
+
+"use strict";
+
+/** @typedef {import("./ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
+/** @typedef {import("./ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
+
+/** @typedef {Error & { cause?: unknown, errors: EXPECTED_ANY[] }} AggregateError */
+
+class AggregateErrorSerializer {
+	/**
+	 * @param {AggregateError} obj error
+	 * @param {ObjectSerializerContext} context context
+	 */
+	serialize(obj, context) {
+		context.write(obj.errors);
+		context.write(obj.message);
+		context.write(obj.stack);
+		context.write(obj.cause);
+	}
+
+	/**
+	 * @param {ObjectDeserializerContext} context context
+	 * @returns {AggregateError} error
+	 */
+	deserialize(context) {
+		const errors = context.read();
+		// eslint-disable-next-line n/no-unsupported-features/es-builtins, n/no-unsupported-features/es-syntax, unicorn/error-message
+		const err = new AggregateError(errors);
+
+		err.message = context.read();
+		err.stack = context.read();
+		err.cause = context.read();
+
+		return err;
+	}
+}
+
+module.exports = AggregateErrorSerializer;