fix workbench otel http span timing (#1815)

internal/cloud/server-workbench-http.ts

@@ -124,6 +124,13 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
   const activeTraceId = requestedTraceId
     ?? safeTraceId(initialSession?.lastTraceId ?? initialSessionSnapshot.lastTraceId ?? initialSessionSnapshot.currentTraceId)
     ?? null;
+  attachWorkbenchRealtimeOtelContext(request, {
+    sessionId: streamSessionId ?? requestedSessionId,
+    traceId: activeTraceId,
+    threadId: streamThreadId,
+    heartbeatMs,
+    outboxMode: typeof (options.runtimeStore ?? null)?.readWorkbenchProjectionOutbox === "function"
+  });
   if (activeTraceId) {
     await (perf ? perf.measure("workbench_initial_trace", () => writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "initial" })) : writeTraceRealtimeSnapshot({ writeEvent, options, actor: auth.actor, traceId: activeTraceId, reason: "initial" }));
     const runtimeStore = options.runtimeStore ?? null;
@@ -222,6 +229,22 @@ export async function handleWorkbenchRealtimeHttp(request, response, url, option
   });
 }
 
+function attachWorkbenchRealtimeOtelContext(request, fields = {}) {
+  const context = request?.hwlabHttpRequestContext;
+  if (!context) return;
+  context.route = "/v1/workbench/events";
+  context.otelAttributes = {
+    ...(context.otelAttributes ?? {}),
+    "workbench.route": "events",
+    "workbench.session_id": fields.sessionId ?? null,
+    traceId: fields.traceId ?? null,
+    "workbench.trace_id": fields.traceId ?? null,
+    "workbench.thread_id": fields.threadId ?? null,
+    "workbench.sse.heartbeat_ms": fields.heartbeatMs ?? null,
+    "workbench.sse.outbox_mode": fields.outboxMode === true
+  };
+}
+
 function realtimeEventCreatedAt(payload) {
   const candidates = [payload?.event?.createdAt, payload?.snapshot?.lastEvent?.createdAt, payload?.turn?.updatedAt];
   for (const value of candidates) {