fix: correlate health metrics by session

Include the live Data Explorer session ID on health ingestion requests so backend logs can join directly to Portal telemetry.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 68ccefda-9e7d-4b01-a4db-e390810491ee

src/Metrics/MetricEvents.test.ts

@@ -1,4 +1,6 @@
+import { HttpHeaders } from "../Common/Constants";
 import { configContext, Platform } from "../ConfigContext";
+import { userContext } from "../UserContext";
 import { getAuthorizationHeader } from "../Utils/AuthorizationUtils";
 import { fetchWithTimeout } from "../Utils/FetchWithTimeout";
 import { MetricScenario } from "./Constants";
@@ -40,11 +42,13 @@ describe("MetricEvents", () => {
 
     const callArgs = mockFetchWithTimeout.mock.calls[0];
     expect(callArgs[0]).toContain("/api/dataexplorer/metrics/health");
-    expect(callArgs[1]?.headers).toEqual({
+    expect(callArgs[1]?.headers).toMatchObject({
       "Content-Type": "application/json",
       authorization: "Bearer test-token",
     });
 
+    expect((callArgs[1]?.headers as Record<string, string>)[HttpHeaders.sessionId]).toBe(userContext.sessionId);
+
     const body = JSON.parse(callArgs[1]?.body as string);
     expect(body.scenario).toBe(MetricScenario.ApplicationLoad);
     expect(body.platform).toBe(Platform.Portal);

src/Metrics/MetricEvents.ts

@@ -1,7 +1,9 @@
 // Metrics module: scenario metric emission logic.
 import { MetricEvent, MetricScenario } from "Metrics/Constants";
+import { HttpHeaders } from "../Common/Constants";
 import { createUri } from "../Common/UrlUtility";
 import { configContext } from "../ConfigContext";
+import { userContext } from "../UserContext";
 import { getAuthorizationHeader } from "../Utils/AuthorizationUtils";
 import { fetchWithTimeout } from "../Utils/FetchWithTimeout";
 
@@ -21,7 +23,11 @@ const send = async (event: MetricEvent): Promise<Response> => {
 
   return await fetchWithTimeout(url, {
     method: "POST",
-    headers: { "Content-Type": "application/json", [authHeader.header]: authHeader.token },
+    headers: {
+      "Content-Type": "application/json",
+      [authHeader.header]: authHeader.token,
+      [HttpHeaders.sessionId]: userContext.sessionId,
+    },
     body: JSON.stringify(event),
   });
 };