Please introduce a system that fills long-running matchmaking queues with bots after 5 minutes, while also allowing players to opt into backfilling ongoing matches.

If enough human players cannot be found after 5 minutes, the match should start with bots rather than leaving players stuck in an endless queue. At the same time, add an optional setting such as "Join ongoing matches" that allows players to join matches that are already in progress.

Players who enable this option could replace bots in matches where a player has left, or join matches that originally started with bots. This would provide another way to get players into matches while also gradually replacing bots with real players as they become available.

Together, these changes would ensure that players never have to wait indefinitely for a full lobby, while still providing a way for real players to join and improve matches that started with bots.