feat: 增强 expect 规则系统，支持多种 body 校验方法和操作符

- 新增 body 分组校验：contains、regex、json（JSONPath）、css（CSS选择器）、xpath
- 新增操作符系统：equals、contains、match、empty、exists、gte、lte、gt、lt
- 新增 headers 响应头校验
- 引入 cheerio、xpath、@xmldom/xmldom 依赖
- BREAKING: expect.bodyContains 迁移至 expect.body.contains

tests/server/app.test.ts

@@ -141,7 +141,9 @@ describe("API 路由", () => {
 
   test("无效 limit 参数返回 400", async () => {
     const targets = store.getTargets();
-    const response = await fetchHandler(new Request(`http://localhost/api/targets/${targets[0]!.id}/history?limit=abc`));
+    const response = await fetchHandler(
+      new Request(`http://localhost/api/targets/${targets[0]!.id}/history?limit=abc`),
+    );
     const body = await response.json();
 
     expect(response.status).toBe(400);