feat(sdk): page_view 增加 nav_type/prerendering 来源信号（预渲染=AI搜索指纹）

Co-Authored-By: Claude Code <noreply@anthropic.com>

sdk/src/events.ts

@@ -2,6 +2,20 @@ import type { Transport } from "./transport";
 import { pageContext } from "./context";
 import { uuid } from "./util";
 
+// 来源信号（Navigation Timing L2）：startPageTracking 仅 init 时调用一次，
+// 读一次 Navigation Entry 即冻结进 page_view——nav_type ∈ navigate/reload/
+// back_forward（浏览器不给则空串）；activationStart>0 = 页面由预渲染激活
+// （AI 搜索/聚合器预加载的强指纹）。任何环境异常静默（spec §4.5 红线）。
+function navSignals(): { nav_type: string; prerendering: boolean } {
+  try {
+    const nav = performance.getEntriesByType("navigation")[0] as
+      { type?: string; activationStart?: number } | undefined;
+    return { nav_type: nav?.type || "", prerendering: (nav?.activationStart ?? 0) > 0 };
+  } catch {
+    return { nav_type: "", prerendering: false };
+  }
+}
+
 // 有效停留（spec §4.3）：页面可见且 30s 内有交互活动才按秒累计 activeMs；
 // 隐藏（visibilitychange→hidden）或离开（pagehide）时发 page_stay 并 flush(true)。
 // close 可能连续触发（hidden 后紧跟 pagehide）：activeMs 清零后不再重发 stay。
@@ -43,9 +57,10 @@ export function startPageTracking(t: Transport) {
     });
   };
   const pc = pageContext();
+  const nav = navSignals(); // init 时读一次冻结，不随时间变
   emit(
     "page_view",
-    { referrer: pc.referrer, referrer_domain: pc.referrer_domain, utm: pc.utm },
+    { referrer: pc.referrer, referrer_domain: pc.referrer_domain, utm: pc.utm, ...nav },
     pc
   );
   const close = () => {

sdk/test/events.test.ts

@@ -41,6 +41,19 @@ async function beaconBodies(siteId: string) {
   return out as { site_id: string; events: { event_name: string; path: string; properties: Record<string, unknown> }[] }[];
 }
 
+/** 桩掉 performance.getEntriesByType（happy-dom 原生 navigation 恒 []）：
+ *  entry=null 模拟无 Navigation API；throwErr 模拟环境异常。afterEach 的
+ *  unstubAllGlobals 负责还原；now 透传 Date.now 以防环境内部偶发调用。 */
+function stubNavigation(entry?: { type: string; activationStart: number } | null, throwErr?: boolean) {
+  vi.stubGlobal("performance", {
+    now: () => Date.now(),
+    getEntriesByType: (type: string) => {
+      if (throwErr) throw new Error("no performance");
+      return type === "navigation" && entry ? [entry] : [];
+    },
+  });
+}
+
 describe("events / startPageTracking", () => {
   beforeEach(() => {
     localStorage.clear();
@@ -56,12 +69,13 @@ describe("events / startPageTracking", () => {
     delete (document as { referrer?: string }).referrer;
   });
 
-  it("page_view 含 path/title/referrer_domain/utm（path 同源清洗）", async () => {
+  it("page_view 含 path/title/referrer_domain/utm/nav_type/prerendering（path 同源清洗）", async () => {
     document.title = "落地页";
     Object.defineProperty(document, "referrer", {
       value: "https://news.example/article/1",
       configurable: true,
     });
+    stubNavigation({ type: "navigate", activationStart: 0 });
     window.history.pushState({}, "", "/land?utm_source=ns&utm_medium=cpc&email=a@b.c");
     const t = mkTransport("site-pv");
     startPageTracking(t);
@@ -78,9 +92,45 @@ describe("events / startPageTracking", () => {
       referrer: "https://news.example/article/1",
       referrer_domain: "news.example",
       utm: { utm_source: "ns", utm_medium: "cpc" },
+      nav_type: "navigate",
+      prerendering: false,
     });
   });
 
+  it("来源信号：activationStart>0 → prerendering=true（AI 搜索/聚合器预渲染指纹）", async () => {
+    stubNavigation({ type: "navigate", activationStart: 100 });
+    const t = mkTransport("site-nav-pp");
+    startPageTracking(t);
+    t.flush();
+
+    const body = JSON.parse(fetchMock.mock.calls[0][1].body);
+    const pv = body.events.find((e: { event_name: string }) => e.event_name === "page_view");
+    expect(pv.properties.nav_type).toBe("navigate");
+    expect(pv.properties.prerendering).toBe(true);
+  });
+
+  it("来源信号降级：无 Navigation API（空数组）或读取抛异常 → 空串/false，page_view 照发不崩", async () => {
+    stubNavigation(null); // getEntriesByType 返回 []
+    let t = mkTransport("site-nav-none");
+    startPageTracking(t);
+    t.flush();
+    let pv = JSON.parse(fetchMock.mock.calls[0][1].body).events.find(
+      (e: { event_name: string }) => e.event_name === "page_view"
+    );
+    expect(pv.properties.nav_type).toBe("");
+    expect(pv.properties.prerendering).toBe(false);
+
+    stubNavigation(undefined, true); // getEntriesByType 抛异常
+    t = mkTransport("site-nav-throw");
+    startPageTracking(t);
+    t.flush();
+    pv = JSON.parse(fetchMock.mock.calls[1][1].body).events.find(
+      (e: { event_name: string }) => e.event_name === "page_view"
+    );
+    expect(pv.properties.nav_type).toBe("");
+    expect(pv.properties.prerendering).toBe(false);
+  });
+
   it("有效停留：可见 + pointerdown 后 3s → close 发 page_stay(active_ms=3000)", async () => {
     window.history.pushState({}, "", "/p4");
     const t = mkTransport("site-t4");