Handle explicitly long running tabs

[benhansen-io]

If someone is using a really long-running tab, their client side code might be old. We should have at least one mechanism to force people to refresh their page.

The experience probably isn't great after 10+ hours of pingings so maybe we should stop the tests on the current page and open a new page?

We might also want an explicit versioning system between the frontend and backend but maybe not yet?