refactor: 统一 expect 断言体系，引入共享 ValueMatcher/ContentRules/KeyValueExpect 模型

- 引入共享 ValueMatcher（equals/contains/regex/exists/empty/gt/gte/lt/lte）
- 引入共享 ContentRules 数组（direct/json/css/xpath 提取器）
- 引入共享 KeyValueExpect（动态键值断言，字面量等价 equals）
- maxDurationMs → durationMs: ValueMatcher（所有 checker）
- match → regex（固定无 flags）
- Ping max* → packetLossPercent/avgLatencyMs/maxLatencyMs（ValueMatcher）
- LLM finishReason/rawFinishReason → ValueMatcher
- DB 新增 result: ContentRules
- TCP banner → ContentRules 数组
- 删除旧模块：operator.ts、validate-operator.ts、duration.ts、body.ts、text.ts、output.ts
- 更新全部 checker schema/validate/expect/execute
- 更新 probe-config.schema.json、probes.example.yaml
- 更新 README.md、DEVELOPMENT.md（含 expect 字段选择规范）
- 同步 10 个 delta specs 到主 specs，归档 change

tests/server/checker/runner/icmp/validate.test.ts

@@ -43,24 +43,24 @@ describe("validatePingConfig", () => {
     expect(issues.some((item) => item.path.endsWith("expect.status"))).toBe(true);
   });
 
-  test("expect 数值非法", () => {
+  test("expect 数值旧字段非法", () => {
     const issues = validate({ expect: { maxPacketLoss: 101 }, id: "ping", ping: { host: "127.0.0.1" }, type: "ping" });
     expect(issues.some((item) => item.path.endsWith("expect.maxPacketLoss"))).toBe(true);
   });
 
-  test("maxDurationMs 类型非法", () => {
-    const issues = validate({ expect: { maxDurationMs: -1 }, id: "ping", ping: { host: "127.0.0.1" }, type: "ping" });
-    expect(issues.some((item) => item.path.endsWith("expect.maxDurationMs"))).toBe(true);
+  test("durationMs 类型非法", () => {
+    const issues = validate({ expect: { durationMs: -1 }, id: "ping", ping: { host: "127.0.0.1" }, type: "ping" });
+    expect(issues.some((item) => item.path.endsWith("expect.durationMs"))).toBe(true);
   });
 
-  test("maxAvgLatencyMs 类型非法", () => {
+  test("avgLatencyMs 类型非法", () => {
     const issues = validate({
-      expect: { maxAvgLatencyMs: "slow" },
+      expect: { avgLatencyMs: "slow" },
       id: "ping",
       ping: { host: "127.0.0.1" },
       type: "ping",
     });
-    expect(issues.some((item) => item.path.endsWith("expect.maxAvgLatencyMs"))).toBe(true);
+    expect(issues.some((item) => item.path.endsWith("expect.avgLatencyMs"))).toBe(true);
   });
 
   test("host 为空字符串", () => {