UPDATE -- the server restart is now done. The games were reset as expected, but the good news is we won't have to deal with this particular problem again. Thank you for your understanding.
So last night's server restart ended up nuking all open games (see https://atwar-game.com/news/news.php?news_id=313).
The bad news is, it's going to happen one more time.
I figured out why it happened, and I have a fix for it. But in order to put the fix in place, I have to restart the server again, and as soon as I do that all the open games will get nuked again. It's a catch-22 that can't be avoided.
It's already a ticking time-bomb... the very next time the server restarts, or crashes for any reason, all the existing games will be gone. There's nothing I can do about it, all the games open now are already bugged, it just hasn't blown up yet.