feat: 新增 TCP checker，支持端口可达性探测与 banner 读取

- 新增 src/server/checker/runner/tcp/ 自包含目录（types/schema/validate/execute/expect）
- 注册 TcpChecker 到 checkerRegistry，schema/engine/store/config-loader 自动委托
- 支持 expect.connected 正反向语义（默认期待可达，可配置期待不可达）
- 支持 readBanner opt-in banner 读取，受 bannerReadTimeout + maxBannerBytes 双重限制
- 复用电有 expect/operator/duration/failure 基础设施
- 新增 3 个测试文件 51 条用例（execute/validate/expect），全量 634 测试通过
- 更新 README/DEVELOPMENT/probes.example.yaml，新增 tcp-checker capability spec

tests/server/checker/config-loader.test.ts

@@ -5,6 +5,7 @@ import { join } from "node:path";
 
 import type { ResolvedCommandTarget } from "../../../src/server/checker/runner/cmd/types";
 import type { ResolvedHttpTarget } from "../../../src/server/checker/runner/http/types";
+import type { ResolvedTcpTarget } from "../../../src/server/checker/runner/tcp/types";
 
 import { loadConfig, parseDuration } from "../../../src/server/checker/config-loader";
 import { checkerRegistry } from "../../../src/server/checker/runner";
@@ -1778,4 +1779,199 @@ targets:
     // eslint-disable-next-line @typescript-eslint/await-thenable
     await expect(loadConfig(configPath)).rejects.toThrow("name");
   });
+
+  test("解析最简 tcp 配置", async () => {
+    const configPath = join(tempDir, "minimal-tcp.yaml");
+    await writeFile(
+      configPath,
+      `targets:
+  - id: "redis-port"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 6379
+`,
+    );
+
+    const config = await loadConfig(configPath);
+    expect(config.targets).toHaveLength(1);
+    const t = config.targets[0]! as ResolvedTcpTarget;
+    expect(t.type).toBe("tcp");
+    expect(t.id).toBe("redis-port");
+    expect(t.name).toBeNull();
+    expect(t.tcp.host).toBe("127.0.0.1");
+    expect(t.tcp.port).toBe(6379);
+    expect(t.tcp.readBanner).toBe(false);
+    expect(t.tcp.bannerReadTimeout).toBe(2000);
+    expect(t.tcp.maxBannerBytes).toBe(4096);
+    expect(t.group).toBe("default");
+    expect(t.intervalMs).toBe(30000);
+    expect(t.timeoutMs).toBe(10000);
+  });
+
+  test("tcp 缺少 host 抛出错误", async () => {
+    await expectConfigError(
+      "tcp-no-host.yaml",
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      port: 80
+`,
+      "tcp.host",
+    );
+  });
+
+  test("tcp 缺少 port 抛出错误", async () => {
+    await expectConfigError(
+      "tcp-no-port.yaml",
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+`,
+      "tcp.port",
+    );
+  });
+
+  test("tcp 非法端口范围抛出错误", async () => {
+    await expectConfigError(
+      "tcp-bad-port.yaml",
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 99999
+`,
+      "tcp.port",
+    );
+  });
+
+  test("tcp 未知分组字段抛出错误", async () => {
+    await expectConfigError(
+      "tcp-unknown-field.yaml",
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 80
+      tls: true
+`,
+      "是未知字段",
+    );
+  });
+
+  test("tcp readBanner 开启并配置 expect.banner", async () => {
+    const configPath = join(tempDir, "tcp-banner.yaml");
+    await writeFile(
+      configPath,
+      `targets:
+  - id: "smtp-check"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 25
+      readBanner: true
+    expect:
+      banner:
+        contains: "ESMTP"
+`,
+    );
+
+    const config = await loadConfig(configPath);
+    const t = config.targets[0]! as ResolvedTcpTarget;
+    expect(t.tcp.readBanner).toBe(true);
+    expect(t.expect?.banner).toEqual({ contains: "ESMTP" });
+  });
+
+  test("tcp expect.banner 未开启 readBanner 抛出错误", async () => {
+    await expectConfigError(
+      "tcp-banner-no-read.yaml",
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 25
+    expect:
+      banner:
+        contains: "ESMTP"
+`,
+      "banner 断言需要启用 tcp.readBanner",
+    );
+  });
+
+  test("tcp defaults 覆盖 banner 参数", async () => {
+    const configPath = join(tempDir, "tcp-defaults.yaml");
+    await writeFile(
+      configPath,
+      `defaults:
+  tcp:
+    bannerReadTimeout: 1000
+    maxBannerBytes: "8KB"
+targets:
+  - id: "t1"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 80
+  - id: "t2"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 81
+      bannerReadTimeout: 3000
+`,
+    );
+
+    const config = await loadConfig(configPath);
+    const t1 = config.targets[0]! as ResolvedTcpTarget;
+    expect(t1.tcp.bannerReadTimeout).toBe(1000);
+    expect(t1.tcp.maxBannerBytes).toBe(8192);
+
+    const t2 = config.targets[1]! as ResolvedTcpTarget;
+    expect(t2.tcp.bannerReadTimeout).toBe(3000);
+    expect(t2.tcp.maxBannerBytes).toBe(8192);
+  });
+
+  test("tcp expect 未知字段抛出错误", async () => {
+    await expectConfigError(
+      "tcp-unknown-expect.yaml",
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 80
+    expect:
+      status: [200]
+`,
+      "是未知字段",
+    );
+  });
+
+  test("tcp expect connected 和 maxDurationMs", async () => {
+    const configPath = join(tempDir, "tcp-expect-connected.yaml");
+    await writeFile(
+      configPath,
+      `targets:
+  - id: "t"
+    type: tcp
+    tcp:
+      host: "127.0.0.1"
+      port: 80
+    expect:
+      connected: false
+      maxDurationMs: 5000
+`,
+    );
+
+    const config = await loadConfig(configPath);
+    const t = config.targets[0]! as ResolvedTcpTarget;
+    expect(t.expect?.connected).toBe(false);
+    expect(t.expect?.maxDurationMs).toBe(5000);
+  });
 });