🔴 Tab/favico badge for users with notifications.

[Lanny]

Currently we poll for notifications in inactive tabs but don't do anything to surface the presence of notifications in the tab/title info.

Could consider using this: https://developer.mozilla.org/en-US/docs/Web/API/Badging_API but there's no FF or safari support so maybe a more traditional approach like swapping the favicon or changing the title text would make more sense.

[robin-macpherson]

For reference, here's what LinkedIn does with theirs: