📦 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/regexp/constructor.js

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

frontend/node_modules/core-js/stable/regexp/dot-all.js

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

frontend/node_modules/core-js/stable/regexp/escape.js

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

frontend/node_modules/core-js/stable/regexp/flags.js

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

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

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

frontend/node_modules/core-js/stable/regexp/match.js

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

frontend/node_modules/core-js/stable/regexp/replace.js

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

frontend/node_modules/core-js/stable/regexp/search.js

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

frontend/node_modules/core-js/stable/regexp/split.js

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

frontend/node_modules/core-js/stable/regexp/sticky.js

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

frontend/node_modules/core-js/stable/regexp/test.js

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

frontend/node_modules/core-js/stable/regexp/to-string.js

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