As a user, I'd like the board to poll for staleness and provide a notification if there are changes at a sane interval

COS:

• Detect when page loses focus and stop doing this so regularly

Testing Notes

Q: How often does this poll? Can the user define this polling interval?
A: 30 sec. No, user can't define interval

Q: What if there was a change, then another change to undo that change? aka there is no effective delta?
A: The client side will receive the updated data and then decide its already up to date, thus ignore it

Q: What if the user has been logged out?
A: Thanks to Jason a separate logic automatically redirects to the login page when an ajax request fails due to being logged out. This works for all requests, be it filter change, detail view, or update poller. The question here probably is whether the update poller should really trigger this redirect...

Q: What if the user does not have permission to see the board? Do they still get notifications?
A: Why would the board open if they had no permission

Q: Any conflict if there was an error on the page as well?
A: Not handled

Q: Is there a way for a user to disable these notifications?
A: No

Q: Any conflict if I have multiple boards open in multiple tabs?
A: Should not. Each board will separately poll for updates though