Looks like the socket partly disconnects from time to time, without the bot actually dying. Maybe there's a missing heartbeat or something?

This is an extension of #1, which I initially assumed was caused by the socket quietly dying. After adding measures to revive the socket if it's closed, it's now clear that the problem is that it quietly dies on Stack's side, while still being kept alive. Effectively, the socket becomes a zombie socket.

I'm not clear on the cause, but neither is anyone else; chat is a piece of crap that hasn't been touched in around 10 years at this point. It's probably a good idea adding a way to detect if messages still appear.

During periods of inactivity, the socket still ends empty messages with no content, so checking if there have been any socket messages in the past X minutes, and restarting otherwise should do the trick.