Streamlit fundamentally runs on websockets [1][2][3] which are currently not supported by the App Runner service. This is a documented service limitation [4].
References:
[1] Can’t deploy streamlit on corporate network: https://discuss.streamlit.io/t/cant-deploy-streamlit-on-corporate-network/2675
[2] Running Streamlit without using Websocket?: https://discuss.streamlit.io/t/running-streamlit-without-using-websocket/34007
[3] Websockets non-negotiable?: https://discuss.streamlit.io/t/websockets-non-negotiable/1078
[4] Support web sockets: Support web sockets · Issue #13 · aws/apprunner-roadmap · GitHub