Remote chat messages missing attributes and attachedFiles when using useChat()

### Description When sending a chat message using `useChat()` with an attachment, the **sender (local)** receives a message object that contains: - `attachedFiles` - `attributes` (if provided) However, the receiver (remote) does not receive these fields at all. They are completely missing, not even present as `undefined`. Remote message object does not contain `attachedFiles` or `attributes` keys. ### Steps to Reproduce Start two clients connected to the same LiveKit room. In one client (sender), call: ```typescript import { useChat } from '@livekit/components-react'; const { chatMessages, isSending, send } = useChat(); const handleSendMessage = async () => { try { setMessageText(''); await send(messageText, { attachments: [file] }); } catch {} } ``` Log `chatMessages` from `useChat()` on both clients. ### Expected Behavior Both the sender and receiver should receive identical message structure, including: ```typescript { message: "...", attachedFiles: [...], attributes: {...}, ... } ``` ### Actual Behavior Sender (local) message object includes both fields: ```typescript { message: "hello", attachedFiles: [File], attributes: { foo: "bar" }, ... } ``` Receiver (remote) message object does not include either field: ```typescript { message: "hello", // attachedFiles → missing // attributes → missing ... } ``` Both fields are entirely absent from the remote message object. ### Code Snippet ```typescript import { useChat } from '@livekit/components-react'; const { chatMessages, send } = useChat(); await send(messageText, { attachments: [file] , attributes: { foo: 'bar' } }); ``` Logging messages: `console.log(chatMessages);` Remote logs show no `attachedFiles` or `attributes` properties at all. ### Describe the proposed solution **Include `attachedFiles` and `attributes` in the chat message** so remote users receive the same structure. ### Alternatives considered _No response_ ### Importance I cannot use LiveKit without it ### Additional Information _No response_