feat(chinese-chess): 实现中国象棋核心逻辑和基本功能

- 抽象出 ChessCore 类，包含游戏初始化、行棋逻辑、悔棋等功能
- 重构 Player 类，优化行棋和记录逻辑
- 更新 ChessBoard 和 ChessPiece 类，适应新逻辑
- 移除冗余代码，提高代码可读性和可维护性

Scripts/Entities/ChessPiece.cs

@@ -7,7 +7,7 @@ public partial class ChessPiece : Sprite2D {
     public string PieceLabel { get; set; } = null;
     // 文字颜色（可导出以编辑器调整）
     [Export]
-    public Color LabelColor { get; set; } = new Color("black");
+    public Color LabelColor { get; set; } = new Color("white");
     private Vector2 textureSize;
 
     private Label labelOfChessName;
@@ -37,12 +37,12 @@ public partial class ChessPiece : Sprite2D {
 		new Vector2(0, 0)
 	);
 
-    public ChessPiece() : this("", Vector2.Zero){
+    public ChessPiece() : this("", new()){
     }
 
-    public ChessPiece(string name, Vector2 pos) {
+    public ChessPiece(string name, VirtualPiece piece) {
         PieceLabel = name;
-        piece = new VirtualPiece(name, pos);
+        this.piece = piece;
         piece.OnMove +=  OnMove;
         piece.OnSelected += OnSelected;
         piece.data = this;