refactor: rename game package to connect4, drop Game prefix from types

Rename game/ -> connect4/ to avoid c4/game stutter. Drop redundant
Game prefix from exported types (GameStore -> Store, GameInstance ->
Instance, GameStatus -> Status). Rename NATS subjects from game.{id}
to connect4.{id}. URL routes unchanged.

features/lobby/routes.go

@@ -2,8 +2,8 @@
 package lobby
 
 import (
+	"github.com/ryanhamamura/c4/connect4"
 	"github.com/ryanhamamura/c4/db/repository"
-	"github.com/ryanhamamura/c4/game"
 	"github.com/ryanhamamura/c4/snake"
 
 	"github.com/alexedwards/scs/v2"
@@ -14,7 +14,7 @@ func SetupRoutes(
 	router chi.Router,
 	queries *repository.Queries,
 	sessions *scs.SessionManager,
-	store *game.GameStore,
+	store *connect4.Store,
 	snakeStore *snake.SnakeStore,
 ) {
 	router.Get("/", HandleLobbyPage(queries, sessions, snakeStore))