refactor: expect 类型模型重构，Raw/Resolved 双层分离与断言基础设施内聚

- 重命名 ContentRules→ContentExpectations, KeyValueExpect→KeyedExpectations
- 新增 Raw/Resolved 双层模型：resolve 阶段物化为执行计划，store 持久化 Raw 快照
- HTTP body 按需读取：status/headers 失败或无 body expectation 时不读取 body
- 新增 displayValueExpectation() 解包 failure.expected 用户可读展示
- 修复 checkEarlyTimeout 独立 lte/lt 检查，修复 KeyedExpectations JSON Schema
- 新增 expect/value.ts(resolve/check/display)、keyed.ts、content.ts、headers.ts、status.ts
- 删除旧 normalize.ts/matcher.ts/validate-matcher.ts/key-value.ts
- 更新 DEVELOPMENT.md：expect 五层管线表、displayValueExpectation、1.7↔1.10 交叉引用
- 同步 13 个 main specs，归档 refactor-expect-type-model 变更（62/62 tasks）

tests/server/checker/runner/shared/body.test.ts

@@ -1,12 +1,15 @@
 import { describe, expect, test } from "bun:test";
 
-import { checkContentRules } from "../../../../../src/server/checker/expect/content";
+import type { RawContentExpectations } from "../../../../../src/server/checker/expect/types";
 
-function checkBodyExpect(body: string, rules?: Parameters<typeof checkContentRules>[1]) {
-  return checkContentRules(body, rules, { path: "body", phase: "body" });
+import { checkContentExpectations, resolveContentExpectations } from "../../../../../src/server/checker/expect/content";
+
+function checkBodyExpect(body: string, rawExpectations?: RawContentExpectations) {
+  const resolved = resolveContentExpectations(rawExpectations);
+  return checkContentExpectations(body, resolved, { path: "body", phase: "body" });
 }
 
-describe("checkBodyExpect (BodyRule[])", () => {
+describe("checkBodyExpect (ContentExpectations)", () => {
   test("无规则返回匹配成功", () => {
     const r = checkBodyExpect("anything");
     expect(r.matched).toBe(true);
@@ -19,6 +22,22 @@ describe("checkBodyExpect (BodyRule[])", () => {
     expect(r.failure).toBeNull();
   });
 
+  test("resolve 输出显式 kind union 并物化 extractor 默认 exists", () => {
+    expect(
+      resolveContentExpectations([
+        { contains: "ok" },
+        { json: { path: "$.status" } },
+        { css: { attr: "content", selector: "meta[name=status]" } },
+        { xpath: { path: "/root/status" } },
+      ]),
+    ).toEqual([
+      { kind: "value", matcher: { contains: "ok" } },
+      { kind: "json", matcher: { exists: true }, path: "$.status" },
+      { attr: "content", kind: "css", matcher: { exists: true }, selector: "meta[name=status]" },
+      { kind: "xpath", matcher: { exists: true }, path: "/root/status" },
+    ]);
+  });
+
   test("contains 规则匹配成功", () => {
     const r = checkBodyExpect("hello world", [{ contains: "hello" }]);
     expect(r.matched).toBe(true);