fix(frontend/builder): auto-scroll to bottom when AI responds in chat panel

autogpt_platform/frontend/src/app/(platform)/build/components/BuilderChatPanel/BuilderChatPanel.tsx

@@ -9,7 +9,7 @@ import {
   StopCircle,
   X,
 } from "@phosphor-icons/react";
-import { KeyboardEvent, useRef, useState } from "react";
+import { KeyboardEvent, useEffect, useRef, useState } from "react";
 import type { CustomNode } from "../FlowEditor/nodes/CustomNode/CustomNode";
 import { GraphAction } from "./helpers";
 import { useBuilderChatPanel } from "./useBuilderChatPanel";
@@ -38,6 +38,11 @@ export function BuilderChatPanel({ className, isGraphLoaded }: Props) {
   const messagesEndRef = useRef<HTMLDivElement>(null);
   const isStreaming = status === "streaming" || status === "submitted";
 
+  // Scroll to bottom whenever a new message lands (AI response or user send)
+  useEffect(() => {
+    messagesEndRef.current?.scrollIntoView({ behavior: "smooth" });
+  }, [messages.length]);
+
   function handleSend() {
     const text = inputValue.trim();
     if (!text || isStreaming) return;