refactor: 引入 Checker 统一接口与 Runner 抽象机制

定义 Checker 接口（resolve/execute/serialize）和 CheckerRegistry
注册中心，消除 engine/config-loader/store 中硬编码类型分支。
按 checker 类型分子包（runner/http/、runner/command/），提取
共享 expect 到 runner/shared/。超时控制通过引擎注入 AbortSignal。
CheckFailure.phase 从联合类型改为 string。配置校验下沉到各
Checker.resolve() 内部。

新增 checker-runner-abstraction spec，更新 DEVELOPMENT.md。

tests/server/checker/runner/http/expect.test.ts

@@ -0,0 +1,142 @@
+import { describe, expect, test } from "bun:test";
+import { checkHttpExpect } from "../../../../../src/server/checker/runner/http/expect";
+
+function obs(overrides: { statusCode?: number; headers?: Record<string, string>; body?: string | null; durationMs?: number } = {}) {
+  return {
+    statusCode: overrides.statusCode ?? 200,
+    headers: overrides.headers ?? {},
+    body: overrides.body ?? "",
+    durationMs: overrides.durationMs ?? 100,
+  };
+}
+
+describe("checkHttpExpect", () => {
+  test("无 expect 配置时默认检查 status [200] 匹配成功", () => {
+    const r = checkHttpExpect(obs().statusCode, obs().headers, obs().body as string, obs().durationMs);
+    expect(r.matched).toBe(true);
+    expect(r.failure).toBeNull();
+  });
+
+  test("无 expect 配置时 status 非 200 匹配失败", () => {
+    const r = checkHttpExpect(500, {}, "", 100);
+    expect(r.matched).toBe(false);
+    expect(r.failure).not.toBeNull();
+    expect(r.failure!.phase).toBe("status");
+    expect(r.failure!.kind).toBe("mismatch");
+  });
+
+  test("status 匹配指定状态码", () => {
+    const cfg = { status: [200, 301] };
+    expect(checkHttpExpect(200, {}, "", 100, cfg).matched).toBe(true);
+    expect(checkHttpExpect(301, {}, "", 100, cfg).matched).toBe(true);
+    expect(checkHttpExpect(404, {}, "", 100, cfg).matched).toBe(false);
+  });
+
+  test("status 不匹配返回 phase=status 的失败", () => {
+    const r = checkHttpExpect(503, {}, "", 100, { status: [200] });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.phase).toBe("status");
+    expect(r.failure!.expected).toEqual([200]);
+    expect(r.failure!.actual).toBe(503);
+  });
+
+  test("duration 在限制内匹配成功", () => {
+    const r = checkHttpExpect(200, {}, "", 50, { maxDurationMs: 100 });
+    expect(r.matched).toBe(true);
+  });
+
+  test("duration 超过限制匹配失败", () => {
+    const r = checkHttpExpect(200, {}, "", 200, { maxDurationMs: 100 });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.phase).toBe("duration");
+  });
+
+  test("duration 恰好等于限制匹配成功", () => {
+    const r = checkHttpExpect(200, {}, "", 100, { maxDurationMs: 100 });
+    expect(r.matched).toBe(true);
+  });
+
+  test("headers 字符串格式检查（等于）", () => {
+    const h = { "content-type": "application/json", "x-api": "v1" };
+    expect(checkHttpExpect(200, h, "", 100, { headers: { "content-type": "application/json" } }).matched).toBe(true);
+    expect(checkHttpExpect(200, h, "", 100, { headers: { "content-type": "text/html" } }).matched).toBe(false);
+  });
+
+  test("headers 操作符格式检查", () => {
+    const h = { "content-type": "application/json" };
+    expect(checkHttpExpect(200, h, "", 100, { headers: { "content-type": { contains: "json" } } }).matched).toBe(true);
+    expect(checkHttpExpect(200, h, "", 100, { headers: { "content-type": { match: "^application/" } } }).matched).toBe(true);
+    expect(checkHttpExpect(200, h, "", 100, { headers: { "content-type": { contains: "xml" } } }).matched).toBe(false);
+  });
+
+  test("headers 大小写不敏感匹配", () => {
+    const h = { "content-type": "application/json" };
+    expect(checkHttpExpect(200, h, "", 100, { headers: { "Content-Type": "application/json" } }).matched).toBe(true);
+  });
+
+  test("headers 不存在时返回失败", () => {
+    const r = checkHttpExpect(200, {}, "", 100, { headers: { "x-missing": "value" } });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.phase).toBe("headers");
+  });
+
+  test("body 规则数组按顺序检查", () => {
+    const body = JSON.stringify({ status: "ok", count: 5 });
+    const r = checkHttpExpect(200, {}, body, 100, {
+      body: [{ contains: "ok" }, { json: { path: "$.count", gte: 1 } }],
+    });
+    expect(r.matched).toBe(true);
+  });
+
+  test("body 第一条规则失败立即返回", () => {
+    const r = checkHttpExpect(200, {}, "hello world", 100, {
+      body: [{ contains: "missing" }, { contains: "hello" }],
+    });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.path).toBe("body[0]");
+  });
+
+  test("body 为 null 但有 body 规则时报错", () => {
+    const r = checkHttpExpect(200, {}, null, 100, { body: [{ contains: "test" }] });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.kind).toBe("error");
+  });
+
+  test("完整流水线 status->duration->headers->body 全部通过", () => {
+    const r = checkHttpExpect(200, { "content-type": "application/json" }, JSON.stringify({ status: "healthy" }), 50, {
+      status: [200],
+      maxDurationMs: 100,
+      headers: { "content-type": { contains: "json" } },
+      body: [{ json: { path: "$.status", equals: "healthy" } }],
+    });
+    expect(r.matched).toBe(true);
+    expect(r.failure).toBeNull();
+  });
+
+  test("完整流水线 status 通过但 duration 失败", () => {
+    const r = checkHttpExpect(200, {}, "", 500, { status: [200], maxDurationMs: 100 });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.phase).toBe("duration");
+  });
+
+  test("完整流水线 status 和 duration 通过但 headers 失败", () => {
+    const r = checkHttpExpect(200, { "x-api": "v1" }, "", 50, {
+      status: [200],
+      maxDurationMs: 100,
+      headers: { "x-api": "v2" },
+    });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.phase).toBe("headers");
+  });
+
+  test("完整流水线 status/duration/headers 通过但 body 失败", () => {
+    const r = checkHttpExpect(200, { "content-type": "text/plain" }, "error occurred", 50, {
+      status: [200],
+      maxDurationMs: 100,
+      headers: { "content-type": "text/plain" },
+      body: [{ contains: "success" }],
+    });
+    expect(r.matched).toBe(false);
+    expect(r.failure!.phase).toBe("body");
+  });
+});