Fix Jupyter workspace session handoff

frontend/app/components/assistant-ui/thread.tsx

@@ -83,6 +83,7 @@ import {
 	clearActiveSessionId,
 	readActiveSessionId,
 	writeActiveSessionId,
+	writePendingWorkspaceSessionId,
 } from "@/lib/claw-active-session";
 import { useClawSessionReplay } from "@/lib/claw-session-replay";
 import { cn } from "@/lib/utils";
@@ -437,6 +438,7 @@ function WorkspaceSwitchDialog({
 		setSubmitting(true);
 		const progressTimer = startWorkspaceProgress(setProgress);
 		try {
+			const needsFirstMessageSession = !normalizeSessionId(sessionId);
 			const response = await fetch("/api/claw/jupyter", {
 				method: "POST",
 				headers: { "content-type": "application/json" },
@@ -455,6 +457,9 @@ function WorkspaceSwitchDialog({
 				return;
 			}
 			writeActiveSessionId(sessionIdForRequest);
+			if (needsFirstMessageSession) {
+				writePendingWorkspaceSessionId(sessionIdForRequest);
+			}
 			setStatus(payload as JupyterWorkspaceStatus);
 			setProgress({ percent: 100, label: "切换完成" });
 			setMessage("工作区切换成功，后续工具会在远端 Jupyter 工作区执行。");