docs: send Ask AI locale per-message to avoid stale transport

useChat keeps the first transport, so the locale baked into it went stale after
a language switch (retrieval stuck on the old locale). Send locale per-message
instead; transport is now stable.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ouiliame

apps/docs/components/ai/ask-ai.tsx

@@ -50,10 +50,9 @@ export function AskAI({ locale }: AskAIProps) {
   const [input, setInput] = useState('')
   const scrollRef = useRef<HTMLDivElement>(null)
 
-  const transport = useMemo(
-    () => new DefaultChatTransport({ api: '/api/chat', body: { locale } }),
-    [locale]
-  )
+  // Stable transport; the locale is sent per-message (below) so it stays current
+  // after a language switch instead of being frozen into the transport.
+  const transport = useMemo(() => new DefaultChatTransport({ api: '/api/chat' }), [])
 
   const { messages, sendMessage, status, stop, error } = useChat({ transport })
 
@@ -74,7 +73,7 @@ export function AskAI({ locale }: AskAIProps) {
     event.preventDefault()
     const text = input.trim()
     if (!text || isBusy) return
-    sendMessage({ text })
+    sendMessage({ text }, { body: { locale } })
     setInput('')
   }