📦 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/runtime/EnsureChunkRuntimeModule.js

@@ -0,0 +1,69 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+*/
+
+"use strict";
+
+const RuntimeGlobals = require("../RuntimeGlobals");
+const RuntimeModule = require("../RuntimeModule");
+const Template = require("../Template");
+
+/** @typedef {import("../Compilation")} Compilation */
+/** @typedef {import("../Module").ReadOnlyRuntimeRequirements} ReadOnlyRuntimeRequirements */
+
+class EnsureChunkRuntimeModule extends RuntimeModule {
+	/**
+	 * @param {ReadOnlyRuntimeRequirements} runtimeRequirements runtime requirements
+	 */
+	constructor(runtimeRequirements) {
+		super("ensure chunk");
+		/** @type {ReadOnlyRuntimeRequirements} */
+		this.runtimeRequirements = runtimeRequirements;
+	}
+
+	/**
+	 * @returns {string | null} runtime code
+	 */
+	generate() {
+		const compilation = /** @type {Compilation} */ (this.compilation);
+		const { runtimeTemplate } = compilation;
+		// Check if there are non initial chunks which need to be imported using require-ensure
+		if (this.runtimeRequirements.has(RuntimeGlobals.ensureChunkHandlers)) {
+			const withFetchPriority = this.runtimeRequirements.has(
+				RuntimeGlobals.hasFetchPriority
+			);
+			const handlers = RuntimeGlobals.ensureChunkHandlers;
+			return Template.asString([
+				`${handlers} = {};`,
+				"// This file contains only the entry chunk.",
+				"// The chunk loading function for additional chunks",
+				`${RuntimeGlobals.ensureChunk} = ${runtimeTemplate.basicFunction(
+					`chunkId${withFetchPriority ? ", fetchPriority" : ""}`,
+					[
+						`return Promise.all(Object.keys(${handlers}).reduce(${runtimeTemplate.basicFunction(
+							"promises, key",
+							[
+								`${handlers}[key](chunkId, promises${
+									withFetchPriority ? ", fetchPriority" : ""
+								});`,
+								"return promises;"
+							]
+						)}, []));`
+					]
+				)};`
+			]);
+		}
+		// There ensureChunk is used somewhere in the tree, so we need an empty requireEnsure
+		// function. This can happen with multiple entrypoints.
+		return Template.asString([
+			"// The chunk loading function for additional chunks",
+			"// Since all referenced chunks are already included",
+			"// in this file, this function is empty here.",
+			`${RuntimeGlobals.ensureChunk} = ${runtimeTemplate.returningFunction(
+				"Promise.resolve()"
+			)};`
+		]);
+	}
+}
+
+module.exports = EnsureChunkRuntimeModule;