Point this copy at a shared endpoint and everyone who does the same will read and write
one schedule. Any service that can serve GET and accept PUT
of JSON will work — a Power Automate HTTP trigger, an Azure Function, Supabase, or a
hosted JSON bin.
null, so
Access-Control-Allow-Origin: * is usually needed. The auth value is stored in
this browser in plain text — use a low-privilege key, not an admin credential.