> Doesn't this mean that the SPA will only be enabled/loaded when the sidebar is open? Isn't that a regression?

As discussed on irc, this a regression. Talkilla is capable of starting up and signing in and receiving calls without the sidebar being shown (it can take 20s for Talkilla to log in, on current production, but it will do it).

If we're not going to store the SPA credentials in cookies, then I think we can land this as-is (once review complete) and do a follow-up as part of the same card to store SPA credentials in the worker so that SPAs can be started up without the sidebar or other UI open.