Update Gallery Websockets example

I think there's a better example here: https://github.com/AnswerDotAI/fasthtml/blob/main/examples/chat_ws.py

Review the current chat app and the new one and determine if it should be replaced, or if it serves a different purpose where both examples should be on the gallery.

Review the current Gallery Websockets example and compare it with examples/chat_ws.py from the linked FastHTML repository. Determine whether the new example should replace the current one or whether both serve distinct purposes. Done means the gallery contains the appropriate example or examples, with the choice documented in the issue or resulting change.

Written by the indexing model from the issue text.