📦 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/ids/NaturalModuleIdsPlugin.js

@@ -0,0 +1,40 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Florent Cailhol @ooflorent
+*/
+
+"use strict";
+
+const {
+	compareModulesByPreOrderIndexOrIdentifier
+} = require("../util/comparators");
+const {
+	assignAscendingModuleIds,
+	getUsedModuleIdsAndModules
+} = require("./IdHelpers");
+
+/** @typedef {import("../Compiler")} Compiler */
+
+const PLUGIN_NAME = "NaturalModuleIdsPlugin";
+
+class NaturalModuleIdsPlugin {
+	/**
+	 * Apply the plugin
+	 * @param {Compiler} compiler the compiler instance
+	 * @returns {void}
+	 */
+	apply(compiler) {
+		compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
+			compilation.hooks.moduleIds.tap(PLUGIN_NAME, () => {
+				const [usedIds, modulesInNaturalOrder] =
+					getUsedModuleIdsAndModules(compilation);
+				modulesInNaturalOrder.sort(
+					compareModulesByPreOrderIndexOrIdentifier(compilation.moduleGraph)
+				);
+				assignAscendingModuleIds(usedIds, modulesInNaturalOrder, compilation);
+			});
+		});
+	}
+}
+
+module.exports = NaturalModuleIdsPlugin;