📦 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/core-js/stable/reflect/apply.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/apply');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/construct.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/construct');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/define-property.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/define-property');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/delete-property.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/delete-property');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/get-own-property-descriptor.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/get-own-property-descriptor');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/get-prototype-of.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/get-prototype-of');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/get.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/get');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/has.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/has');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/index.js

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+'use strict';
+var parent = require('../../es/reflect');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/is-extensible.js

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+'use strict';
+var parent = require('../../es/reflect/is-extensible');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/own-keys.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/own-keys');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/prevent-extensions.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/prevent-extensions');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/set-prototype-of.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/set-prototype-of');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/set.js

@@ -0,0 +1,4 @@
+'use strict';
+var parent = require('../../es/reflect/set');
+
+module.exports = parent;

frontend/node_modules/core-js/stable/reflect/to-string-tag.js

@@ -0,0 +1,4 @@
+'use strict';
+require('../../modules/es.reflect.to-string-tag');
+
+module.exports = 'Reflect';