feat: support NEXT_PUBLIC_LANGGRAPH_BASE_URL

frontend/src/core/api/api-client.ts

@@ -2,12 +2,12 @@
 
 import { Client as LangGraphClient } from "@langchain/langgraph-sdk/client";
 
-import { getBackendBaseURL } from "../config";
+import { getLangGraphBaseURL } from "../config";
 
 let _singleton: LangGraphClient | null = null;
 export function getAPIClient(): LangGraphClient {
   _singleton ??= new LangGraphClient({
-    apiUrl: getBackendBaseURL(),
+    apiUrl: getLangGraphBaseURL(),
   });
   return _singleton;
 }