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/icmp/execute.test.ts

@@ -84,7 +84,10 @@ rtt min/avg/max/mdev = 1.234/2.345/3.456/0.567 ms`);
   test("packetLoss 断言失败", async () => {
     mockSpawn(`3 packets transmitted, 2 received, 33% packet loss, time 2003ms
 rtt min/avg/max/mdev = 1.234/156.000/340.000/0.567 ms`);
-    const result = await checker.execute(makeTarget({ expect: { packetLossPercent: { lte: 10 } } }), makeCtx());
+    const result = await checker.execute(
+      makeTarget({ expect: { alive: true, packetLossPercent: { lte: 10 } } }),
+      makeCtx(),
+    );
     expect(result.matched).toBe(false);
     expect(result.failure?.phase).toBe("packetLoss");
     expect(result.observation).toMatchObject({ alive: true, maxLatencyMs: 340 });
@@ -125,6 +128,8 @@ describe("IcmpChecker resolve", () => {
     );
     expect(target.icmp).toEqual({ count: 3, host: "10.0.0.1", packetSize: 56 });
     expect(target.group).toBe("default");
+    expect(target.rawExpect).toBeUndefined();
+    expect(target.expect).toEqual({ alive: true });
   });
 
   test("serialize 返回摘要和配置", () => {