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/shared/body.test.ts

@@ -1,6 +1,10 @@
 import { describe, expect, test } from "bun:test";
 
-import { checkBodyExpect } from "../../../../../src/server/checker/runner/http/body";
+import { checkContentRules } from "../../../../../src/server/checker/expect/content";
+
+function checkBodyExpect(body: string, rules?: Parameters<typeof checkContentRules>[1]) {
+  return checkContentRules(body, rules, { path: "body", phase: "body" });
+}
 
 describe("checkBodyExpect (BodyRule[])", () => {
   test("无规则返回匹配成功", () => {
@@ -57,7 +61,7 @@ describe("checkBodyExpect (BodyRule[])", () => {
   test("json 操作符匹配", () => {
     const body = JSON.stringify({ count: 42, version: "v2.1.0" });
     expect(checkBodyExpect(body, [{ json: { gte: 10, path: "$.count" } }]).matched).toBe(true);
-    expect(checkBodyExpect(body, [{ json: { match: "\\d+\\.\\d+\\.\\d+", path: "$.version" } }]).matched).toBe(true);
+    expect(checkBodyExpect(body, [{ json: { path: "$.version", regex: "\\d+\\.\\d+\\.\\d+" } }]).matched).toBe(true);
     expect(checkBodyExpect(body, [{ json: { gte: 100, path: "$.count" } }]).matched).toBe(false);
   });