feat: enrich AgentRun dispatch error OTel spans

internal/cloud/server-code-agent-http.ts

@@ -829,10 +829,11 @@ async function submitCodeAgentChatTurn({ params, options, traceId }) {
         });
       } catch (error) {
         if (isCodeAgentResultCanceled(results.get(traceId))) return;
+        const dispatchErrorAttributes = codeAgentDispatchErrorOtelAttributes(error);
         void emitCodeAgentOtelSpan("agentrun_dispatch", traceId, executionOptions.env ?? process.env, {
           status: "error",
           error,
-          attributes: { sessionId: safeSessionId(params.sessionId) || null, turnId: codeAgentTurnLifecycleFields(traceId, params).turnId }
+          attributes: { sessionId: safeSessionId(params.sessionId) || null, turnId: codeAgentTurnLifecycleFields(traceId, params).turnId, ...dispatchErrorAttributes }
         });
         await settleAdmittedCodeAgentFailure({
           base: initial ?? codeAgentAdmittedFailureBasePayload({ params, options, traceId }),
@@ -1028,6 +1029,23 @@ function codeAgentDispatchFailure(error) {
   };
 }
 
+function codeAgentDispatchErrorOtelAttributes(error) {
+  const agentRunError = error?.agentRunError && typeof error.agentRunError === "object" ? error.agentRunError : null;
+  const details = agentRunError?.error?.details && typeof agentRunError.error.details === "object" ? agentRunError.error.details : null;
+  return {
+    failureKind: safeOtelText(error?.code ?? agentRunError?.failureKind, 120),
+    upstreamStatusCode: Number.isInteger(error?.statusCode) ? error.statusCode : null,
+    upstreamTraceId: safeTraceId(agentRunError?.traceId) || null,
+    upstreamMessage: safeOtelText(agentRunError?.message ?? error?.message, 300),
+    upstreamStderrTail: safeOtelText(details?.stderr, 600)
+  };
+}
+
+function safeOtelText(value, limit = 300) {
+  const text = String(value ?? "").replace(/[\u0000-\u001f\u007f]+/gu, " ").trim();
+  return text ? text.slice(0, limit) : null;
+}
+
 function codeAgentAdmittedFailureBasePayload({ params = {}, options = {}, traceId } = {}) {
   const now = new Date().toISOString();
   return {