fix(integrations): select newest ISP metric period explicitly

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/integrations/src/unifi-os/test/unifi-sm-api.spec.ts

@@ -79,6 +79,39 @@ describe("UnifiSmApi getIspMetricsAsync", () => {
     });
   });
 
+  test("returns the newest period by metricTime even when periods arrive out of order", async () => {
+    const fetchAsync = vi.fn(async (url: string, _init?: RequestInit) => {
+      if (!url.includes("isp-metrics")) return jsonResponse(sitesBody);
+
+      return jsonResponse({
+        data: {
+          metrics: [
+            {
+              periods: [
+                {
+                  metricTime: "2026-09-08T09:10:00Z",
+                  data: {
+                    wan: { avgLatency: 11, maxLatency: 12, packetLoss: 0, uptime: 100, ispName: "Example ISP" },
+                  },
+                },
+                {
+                  metricTime: "2026-09-08T08:00:00Z",
+                  data: { wan: { avgLatency: 99, maxLatency: 99, packetLoss: 5, uptime: 90, ispName: "Old" } },
+                },
+              ],
+            },
+          ],
+        },
+      });
+    });
+    const api = new UnifiSmApi("cloud-key", fetchAsync as never);
+
+    const metrics = await api.getIspMetricsAsync(GATEWAY_MAC);
+
+    expect(metrics?.latencyMs).toBe(11);
+    expect(metrics?.measuredAt).toEqual(new Date("2026-09-08T09:10:00Z"));
+  });
+
   test("returns null when no cloud site matches, never another account site", async () => {
     const { api } = createApi();
 

packages/integrations/src/unifi-os/unifi-sm-api.ts

@@ -115,7 +115,10 @@ export class UnifiSmApi {
     );
 
     const periods = parsed.data.metrics[0]?.periods ?? [];
-    const latest = periods.at(-1);
+    const latest = periods.reduce<(typeof periods)[number] | undefined>((newest, period) => {
+      if (newest === undefined) return period;
+      return new Date(period.metricTime).getTime() > new Date(newest.metricTime).getTime() ? period : newest;
+    }, undefined);
     const wan = latest?.data.wan;
     if (latest === undefined || wan === undefined) return null;