📦 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/fast-glob/out/readers/async.js

@@ -0,0 +1,35 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const fsWalk = require("@nodelib/fs.walk");
+const reader_1 = require("./reader");
+const stream_1 = require("./stream");
+class ReaderAsync extends reader_1.default {
+    constructor() {
+        super(...arguments);
+        this._walkAsync = fsWalk.walk;
+        this._readerStream = new stream_1.default(this._settings);
+    }
+    dynamic(root, options) {
+        return new Promise((resolve, reject) => {
+            this._walkAsync(root, options, (error, entries) => {
+                if (error === null) {
+                    resolve(entries);
+                }
+                else {
+                    reject(error);
+                }
+            });
+        });
+    }
+    async static(patterns, options) {
+        const entries = [];
+        const stream = this._readerStream.static(patterns, options);
+        // After #235, replace it with an asynchronous iterator.
+        return new Promise((resolve, reject) => {
+            stream.once('error', reject);
+            stream.on('data', (entry) => entries.push(entry));
+            stream.once('end', () => resolve(entries));
+        });
+    }
+}
+exports.default = ReaderAsync;