Agent Spec integration emits TextMessageChunk instead of TextMessageContent

I dunno if this was intentional, but the agent-spec/python integration appears to be emitting TextMessageChunk events rather than TextMessageContent events.

It seems to differ from how other integrations work. I know that the docs say that TextMessageChunk is supposed to expand out to TextMessageStart, TextMessageContent, and TextMessageEnd automatically, but the events I'm observing in my SSE stream just show the TextMessageChunk events only. Is this auto-expansion expected to be handled manually by the consuming client?

Also, it seems like we have a missed opportunity here when the `langgraph` runtime is in use with the integration, the `LangGraphAgent` adapter from the `ag-ui-langgraph` package could be leveraged to maintain consistent behavior. Was there a reason why it's not being used for that runtime?

UPDATE: Okay, I just tried using `LangGraphAgent`, and `add_langgraph_fastapi_endpoint` from the `ag-ui-langgraph` package directly instead of `ag-ui-agent-spec`, and it appears to be working.

Thanks.