Add a Hide-and-Seek Game Mode

Add a game mode in which one player is selected as the seeker while all other players must hide. The hiding team would receive a short preparation period before the seeker is released. The seeker would be armed and must find and eliminate every hidden player before the round timer expires. The seeker wins by eliminating all remaining players, while the hiding team wins if at least one player survives until the end of the round. The seeker role could rotate between players after each round.