📦 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/@rushstack/eslint-patch/lib-dts/_patch-base.d.ts

@@ -0,0 +1,13 @@
+declare const isModuleResolutionError: (ex: unknown) => boolean;
+declare let eslintFolder: string | undefined;
+export declare const eslintPackageVersion: string;
+declare const ESLINT_MAJOR_VERSION: number;
+declare let configArrayFactory: any;
+declare let ModuleResolver: {
+    resolve: any;
+};
+declare let Naming: {
+    normalizePackageName: any;
+};
+export { eslintFolder, configArrayFactory, ModuleResolver, Naming, ESLINT_MAJOR_VERSION, isModuleResolutionError };
+//# sourceMappingURL=_patch-base.d.ts.map