DEV: patchbot: retrieve the shared state on page load, with a timeout

DEV: patchbot: retrieve the shared state on page load, with a timeout

I got trapped a few times reviewing patches without clicking the
"Get Updates" button (not yet being used to it). After checking with
AI, it's not complicate to implement a fetch timeout, so let's do that
directly on page load. It also means that a reload will automatically
retrieve updates. In case of failure (offline, server dead), after 2s
the fetch is abandonned and the page can be used normally. For browsers
that wouldn't implement the timeout, it would just act as if the button
had been clicked, so likely that pressing Esc would stop it. Tested in
firefox 140.