feat: 重构为多类型 checker 通用框架，支持 HTTP 与命令检查

- 引入 typed target 判别联合，支持 http 与 command 两种 checker
- expect 重构为有序规则数组，按配置顺序快速失败并生成结构化 failure
- 新增 command runner，支持 exec + args 本地命令执行
- 引入全局并发限制 maxConcurrentChecks 和 size 解析 (KB/MB/GB)
- HTTP/command 各自独立 expect pipeline，应用领域默认成功语义
- SQLite schema、API、Dashboard 全链路调整为 checker 通用契约
- 补充完整测试覆盖（192 tests），更新 README 与示例配置

probes.example.yaml

@@ -3,34 +3,207 @@ server:
   port: 3000
   dataDir: "/tmp/probes_data"
 
+runtime:
+  maxConcurrentChecks: 20
+
 defaults:
-  interval: "5s"
+  interval: "30s"
   timeout: "10s"
-  method: "GET"
+  http:
+    method: GET
+    maxBodyBytes: "10MB"
+  command:
+    maxOutputBytes: "1MB"
 
 targets:
-  - name: "Baidu"
-    url: "https://www.baidu.com"
-    expect:
-      status: [200]
-      maxLatencyMs: 10000
+  # ========== HTTP targets ==========
 
-  - name: "JSON API 示例"
-    url: "https://httpbin.org/json"
+  - name: "Baidu 首页可用"
+    type: http
+    http:
+      url: "https://www.baidu.com"
     expect:
       status: [200]
+      maxDurationMs: 5000
+
+  - name: "JSON API — 完整流水线"
+    type: http
+    interval: "1m"
+    timeout: "15s"
+    http:
+      url: "https://httpbin.org/json"
       headers:
-        Content-Type: application/json
+        Accept: "application/json"
+    expect:
+      headers:
+        Content-Type:
+          contains: "application/json"
+      maxDurationMs: 8000
       body:
-        contains: "slideshow"
-        json:
-          $.slideshow.title: "Sample Slide Show"
+        - json:
+            path: "$.slideshow.title"
+            equals: "Sample Slide Show"
+        - json:
+            path: "$.slideshow.slides[0].title"
+            contains: "Wake"
+        - json:
+            path: "$.slideshow.slides[0].type"
+            equals: "all"
+        - regex: '"title"'
 
-  - name: "HTML 页面示例"
-    url: "https://httpbin.org/html"
+  - name: "HTML 页面 — CSS 选择器"
+    type: http
+    http:
+      url: "https://httpbin.org/html"
+    expect:
+      body:
+        - css:
+            selector: "h1"
+            contains: "Moby-Dick"
+        - css:
+            selector: "body"
+            exists: true
+
+  - name: "HTML 页面 — XPath 提取节点文本"
+    type: http
+    http:
+      url: "https://httpbin.org/html"
+    expect:
+      body:
+        - xpath:
+            path: "/html/body/h1/text()"
+            contains: "Melville"
+
+  - name: "POST 接口测试"
+    type: http
+    http:
+      url: "https://httpbin.org/post"
+      method: POST
+      headers:
+        Content-Type: "application/json"
+      body: '{"action":"check","version":1}'
     expect:
       status: [200]
       body:
-        contains: "Moby-Dick"
-        xpath:
-          "/html/body/h1/text()": "Herman Melville - Moby-Dick"
+        - json:
+            path: "$.json.action"
+            equals: "check"
+        - json:
+            path: "$.json.version"
+            gte: 1
+
+  - name: "请求头验证"
+    type: http
+    http:
+      url: "https://httpbin.org/headers"
+      headers:
+        X-Custom-Header: "gateway-checker"
+    expect:
+      status: [200]
+      body:
+        - json:
+            path: "$.headers.X-Custom-Header"
+            equals: "gateway-checker"
+
+  - name: "响应头自定义校验"
+    type: http
+    http:
+      url: "https://httpbin.org/response-headers"
+      headers:
+        accept: "application/json"
+    expect:
+      body:
+        - json:
+            path: "$.Content-Type"
+            equals: "application/json"
+
+  - name: "多状态码允许"
+    type: http
+    http:
+      url: "https://httpbin.org/status/200"
+    expect:
+      status: [200, 201, 204]
+
+  # ========== Command targets ==========
+
+  - name: "uname 输出匹配"
+    type: command
+    command:
+      exec: "uname"
+      args: ["-s"]
+    expect:
+      exitCode: [0]
+      stdout:
+        - match: "^[A-Z][a-z]+$"
+
+  - name: "echo 自定义文本输出"
+    type: command
+    command:
+      exec: "echo"
+      args: ["check ok"]
+    expect:
+      stdout:
+        - equals: "check ok\n"
+      maxDurationMs: 3000
+
+  - name: "ls 目录无 stderr"
+    type: command
+    command:
+      exec: "ls"
+      args: ["/tmp"]
+      cwd: "/"
+    expect:
+      exitCode: [0]
+      stderr:
+        - empty: true
+
+  - name: "date 输出包含年份"
+    type: command
+    command:
+      exec: "date"
+      args: ["+%Y"]
+    expect:
+      stdout:
+        - match: "^20\\d{2}\n?$"
+
+  - name: "wc 行数计数"
+    type: command
+    command:
+      exec: "wc"
+      args: ["-l"]
+      cwd: "/etc"
+      env:
+        LANG: "C"
+    expect:
+      stdout:
+        - match: "\\d+"
+
+  - name: "hostname 非空输出"
+    type: command
+    command:
+      exec: "hostname"
+    expect:
+      stdout:
+        - match: ".+"
+
+  - name: "多规则 stdout 顺序校验"
+    type: command
+    interval: "5m"
+    command:
+      exec: "echo"
+      args: ["version: 2.0.1, status: healthy"]
+    expect:
+      stdout:
+        - contains: "version:"
+        - match: "\\d+\\.\\d+\\.\\d+"
+        - contains: "healthy"
+
+  - name: "stderr 内容检查"
+    type: command
+    command:
+      exec: "ls"
+      args: ["/nonexistent-path-checker-test"]
+    expect:
+      exitCode: [0, 1, 2]
+      stderr:
+        - contains: "No such file"