Flask response
The tracker hang spot:
return render_template("upload.html", group=group, files=names)
Right now Flask builds the whole upload.html and only then flushes. On a tiny 2005 firewall that delay is enough to make the browser think the connection is toast.
đź”§ Minimal adjustment (test mode)
Yes, you can “tack on” Response to your existing imports. You already have:
