optimize to use 1 less bit for color

src/lib/chess/types.ts

@@ -2,6 +2,7 @@ import { Game } from "./utils";
 export type GameListener = (board: Game) => void;
 
 export enum Piece {
+  // bit 0-2: piece type (0-6)
   EMPTY = 0,
   KING = 1,
   QUEEN = 2,
@@ -10,8 +11,9 @@ export enum Piece {
   KNIGHT = 5,
   PAWN = 6,
 
-  WHITE = 8,
-  BLACK = 16,
+  // bit 3: color (0-1)
+  WHITE = 0,
+  BLACK = 8,
 }
 
 export const CHAR_TO_PIECE: Record<string, number> = {