App stuck after "Processed dependencies!" — never starts (no error, no Uvicorn log)

Hey there, thanks for the super detailed report and for sharing all your troubleshooting steps! This “stuck after Processed dependencies!” issue—where the app never logs “Uvicorn server started” or executes any code—is a known symptom on Streamlit Community Cloud, especially when there are no errors or tracebacks and the frontend just shows a blank page. This can be caused by (1) a platform-level issue, (2) a problem with your requirements.txt (such as incompatible, missing, or built-in packages), (3) a Python version mismatch, or (4) a resource or orchestration bug on the backend.