complete performance and reliability follow-ups

packages/observability/test/observability.test.ts

@@ -8,6 +8,8 @@ describe("@wrnexus/observability", () => {
     expect(client).toContain('addEventListener("pagehide", flush');
     expect(client).not.toContain('send("INP",max)');
     expect(client).not.toContain('send("LCP", last.startTime)');
+    expect(client).toContain("web-vitals delivery failed");
+    expect(client).toContain("PerformanceObserver unavailable for");
   });
 
   test("records deterministic counters and histograms", () => {