fix(ai): use LangServe message format (type instead of role)

app/pages/clientarea/ai/index.vue

@@ -87,7 +87,7 @@ const handleSend = async () => {
     const body = {
       input: {
         messages: chat.value.map((m) => ({
-          role: m.role === 'assistant' ? 'assistant' : 'user',
+          type: m.role === 'assistant' ? 'ai' : 'human',
           content: m.content
         }))
       }