feat: 基础设施加固 — 修复构建、数据保留、错误边界、bundle 拆分

- 修复 build script 引用已删除的 registerCheckers，恢复生产构建
- 生产入口添加 SIGINT/SIGTERM 优雅关闭（与 dev.ts 一致）
- 新增 runtime.retention 配置（默认 7d），ProbeStore.prune() 定时清理过期数据
- parseDuration 扩展支持 h/d 单位
- 新增前端 ErrorBoundary 组件，防止渲染错误白屏
- Vite codeSplitting.groups 拆分 vendor chunks（业务代码 1180KB → 47KB）
- 同步 delta specs 到主规范

tests/server/checker/engine.test.ts

@@ -220,4 +220,55 @@ describe("ProbeEngine", () => {
       void httpServer.stop();
     }
   });
+
+  test("retentionMs > 0 时 start 调用 prune", () => {
+    let pruneCalled = false;
+    const mockStore = {
+      ...createMockStore(["test"]),
+      prune() {
+        pruneCalled = true;
+        return 0;
+      },
+    } as unknown as ProbeStore;
+
+    const targets: ResolvedTargetBase[] = [makeCommandTarget("test")];
+    const engine = new ProbeEngine(mockStore, targets, 20, 86400000);
+    engine.start();
+    expect(pruneCalled).toBe(true);
+    engine.stop();
+  });
+
+  test("retentionMs = 0 时不调用 prune", () => {
+    let pruneCalled = false;
+    const mockStore = {
+      ...createMockStore(["test"]),
+      prune() {
+        pruneCalled = true;
+        return 0;
+      },
+    } as unknown as ProbeStore;
+
+    const targets: ResolvedTargetBase[] = [makeCommandTarget("test")];
+    const engine = new ProbeEngine(mockStore, targets, 20, 0);
+    engine.start();
+    expect(pruneCalled).toBe(false);
+    engine.stop();
+  });
+
+  test("retentionMs 未传时不调用 prune", () => {
+    let pruneCalled = false;
+    const mockStore = {
+      ...createMockStore(["test"]),
+      prune() {
+        pruneCalled = true;
+        return 0;
+      },
+    } as unknown as ProbeStore;
+
+    const targets: ResolvedTargetBase[] = [makeCommandTarget("test")];
+    const engine = new ProbeEngine(mockStore, targets);
+    engine.start();
+    expect(pruneCalled).toBe(false);
+    engine.stop();
+  });
 });