fix workbench otel http span timing (#1815)

internal/cloud/server.ts

@@ -131,23 +131,32 @@ export function createCloudApiServer(options = {}) {
     const requestContext = buildHttpRequestContext(request);
     attachHttpRequestContext(request, response, requestContext);
     const backendPerformance = backendPerformanceStore.beginHttpRequest(request, response);
-    response.once("finish", () => {
+    let otelHttpSpanEmitted = false;
+    const emitHttpSpan = (closedBy) => {
+      if (otelHttpSpanEmitted) return;
+      otelHttpSpanEmitted = true;
       const httpCtx = request.hwlabHttpRequestContext;
       if (!httpCtx?.traceId) return;
       if (isOtelNoisyProbeRoute(httpCtx.route)) return;
       const lastError = httpCtx.lastHttpError;
       void emitHttpServerRequestSpan(httpCtx, env, {
-        startTimeMs: backendPerformance.startedAt,
+        startTimeMs: httpCtx.startedAtMs,
         endTimeMs: Date.now(),
         statusCode: Number(response.statusCode ?? backendPerformance.statusCode ?? 0),
         method: backendPerformance.method || httpCtx.method,
         route: backendPerformance.route || httpCtx.route,
+        attributes: {
+          "http.closed_by": closedBy,
+          ...(httpCtx.otelAttributes ?? {})
+        },
         errorCode: lastError?.code,
         errorCategory: lastError?.category,
         errorLayer: lastError?.layer,
         statusMessage: lastError?.code
       }).catch(() => undefined);
-    });
+    };
+    response.once("finish", () => emitHttpSpan("finish"));
+    response.once("close", () => emitHttpSpan("close"));
     await withBackendPerformanceContext(backendPerformance, async () => {
       try {
         await routeRequest(request, response, { ...options, env, runtimeStore, gatewayRegistry, hwpodNodeWsRegistry, accessController, sessionRegistry, traceStore, codexStdioManager, codeAgentChatResults, webPerformanceStore, backendPerformanceStore, backendPerformance });
@@ -178,6 +187,7 @@ function buildHttpRequestContext(request) {
   });
   return {
     requestId: safeRequestId(getHeader(request, "x-request-id")) || `req_${randomUUID()}`,
+    startedAtMs: Date.now(),
     traceId: otelContext.traceId,
     parentSpanId: otelContext.parentSpanId,
     spanId: otelContext.spanId,