doc: add README

feat: cleanup session after disconnect

feat: terminate spectators in game end

feat: remove streaming buffer

feat: reduce spectate delay buffer

feat: player spectate mode

feat: update game engine

fix: goal side logic

refactor: move ready to separate file

doc: important public methods

build: remove old port flag

feat: main context cancellation

fix: position update

feat: terminate conn on read failure

doc: game info struct