feat(consult): open the response stream before preparation, reservation and classification; rejections ride the stream (T2, BUG-1074)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0199rbQDTsUbCVw84wc8BTFe

frontend/src/hooks/use-consultation-run.ts

@@ -863,7 +863,9 @@ export function useConsultationRun(params: ConsultationRunParams) {
       if (!response.body) {
         throw new ConsultationResponseError(502, "浏览器未收到可读取的回答流");
       }
-      responseKind = response.headers.get("x-jyotish-response-kind") === "smalltalk" ? "smalltalk" : undefined;
+      // Whether the reply was smalltalk is only known once the server has
+      // classified the turn, which now happens inside the stream (BUG-1074):
+      // the run.completed event says so; there is no response header for it.
       let techniqueTruth = response.headers.get("x-jyotish-technique-truth") ?? "unknown";
       let workflowReceipt: AgentExecutionReceipt["workflow"] = {
         route: response.headers.get("x-jyotish-workflow-route") ?? "unknown",
@@ -891,6 +893,9 @@ export function useConsultationRun(params: ConsultationRunParams) {
             label: CONSULTATION_CHART_CALCULATION_LABEL,
             completedTrail: activityCompletedTrail([CONSULTATION_DONE_SKILL_LABEL]),
           };
+        } else if (event.type === "activity" && event.phase === "received") {
+          // The stream's first byte, before anything has been done: no trail.
+          activity = { phase: event.phase, label: event.label };
         } else if (event.type === "activity") {
           activity = {
             phase: event.phase,
@@ -957,6 +962,15 @@ export function useConsultationRun(params: ConsultationRunParams) {
               techniqueTruth = event.receipt.techniqueTruth ?? "unknown";
             }
           }
+          if (event.type === "run.failed" && event.code === "request_rejected") {
+            // A rejection the route used to send as a JSON body with an HTTP
+            // status before the stream opened (BUG-1074): same status, same
+            // sentence, same code, so the handling below does not change.
+            const status = event.status ?? 503;
+            if (status === 401) window.location.assign("/login");
+            if (status === 402) openAccountDialog("billing", { source: "insufficient-credits" });
+            throw new ConsultationResponseError(status, payloadMessage({ message: event.message }, "服务暂时不可用"), event.reason);
+          }
           if (event.type === "run.failed") {
             if (event.code === "answer_truncated") {
               truncatedFailure = event;