sf4e rollback: test release 2

Fixes from the first real online match.

• Matches no longer drop on a one-second network hiccup. The disconnect timeout is now ten seconds, with a warning at two.
• Smoother time sync: when one side runs ahead, the game skips simulation frames instead of freezing.
• Network stats (ping, frames behind) are written to the log every ten seconds, so bug reports carry them.

Both players must be on the same release. Install exactly as in test release 1: extract, put the lobby server address in server.txt, run Launcher.exe. Older builds are refused when joining.

The lobby server is unchanged; hosts keep using the server package from test release 1.