📦 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/css-select/lib/pseudo-selectors/index.d.ts

@@ -0,0 +1,8 @@
+import type { CompiledQuery, InternalOptions, CompileToken } from "../types";
+import { PseudoSelector } from "css-what";
+import { filters } from "./filters";
+import { pseudos } from "./pseudos";
+import { aliases } from "./aliases";
+export { filters, pseudos, aliases };
+export declare function compilePseudoSelector<Node, ElementNode extends Node>(next: CompiledQuery<ElementNode>, selector: PseudoSelector, options: InternalOptions<Node, ElementNode>, context: Node[] | undefined, compileToken: CompileToken<Node, ElementNode>): CompiledQuery<ElementNode>;
+//# sourceMappingURL=index.d.ts.map