📦 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/aria-query/lib/util/iterationDecorator.js

@@ -0,0 +1,17 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = iterationDecorator;
+var _iteratorProxy = _interopRequireDefault(require("./iteratorProxy"));
+function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
+function _typeof(o) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (o) { return typeof o; } : function (o) { return o && "function" == typeof Symbol && o.constructor === Symbol && o !== Symbol.prototype ? "symbol" : typeof o; }, _typeof(o); }
+function iterationDecorator(collection, entries) {
+  if (typeof Symbol === 'function' && _typeof(Symbol.iterator) === 'symbol') {
+    Object.defineProperty(collection, Symbol.iterator, {
+      value: _iteratorProxy.default.bind(entries)
+    });
+  }
+  return collection;
+}

frontend/node_modules/aria-query/lib/util/iteratorProxy.js

@@ -0,0 +1,32 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+// eslint-disable-next-line no-unused-vars
+function iteratorProxy() {
+  var values = this;
+  var index = 0;
+  var iter = {
+    '@@iterator': function iterator() {
+      return iter;
+    },
+    next: function next() {
+      if (index < values.length) {
+        var value = values[index];
+        index = index + 1;
+        return {
+          done: false,
+          value: value
+        };
+      } else {
+        return {
+          done: true
+        };
+      }
+    }
+  };
+  return iter;
+}
+var _default = exports.default = iteratorProxy;