Broken After Upgrade to 4.2.2

Moving from 4.1.2 to 4.2.2, I can no longer load my site, and the admin area does not show.

I get the menu bar on the left, but nothing else. I don’t get the utility bar at the top of the page when I’m in the admin area nor when I’m looking at the site.

Because this instance of WordPress happens to be on a server running Plesk, the first thing I did was disable all plugins and reset the default theme. It made no difference. I also manually re-copied the 4.2.2 files via FTP to try following the Manual Update process. Still no improvement.

Here’s what /wp-admin looks like: https://i.imgur.com/YqFCR6v.png

Here’s my debug.log (with [site root] replacing the actual path on disk): https://gist.github.com/anonymous/8f36cea3865277a30f03