chore: 删除无用的项目配置和资源文件修改android key,修正godot4.3无法构建的问题

- 移除 .gitattributes 和 .gitignore 文件
- 删除 Asserts 目录下的棋盘和棋子基础资源文件

Scripts/Utilities/VirtualPiece.cs

@@ -1,40 +0,0 @@
-// using System.Numerics;
-using Godot;
-
-using System;
-
-public class VirtualPiece  {
-    private Vector2 pos; // 注意这个坐标的非像素坐标而是棋盘坐标
-    
-    private string name;
-    private bool isSelected;
-    public object data;
-
-    public event Action<Vector2> OnMove;
-    public event Action<bool> OnSelected;
-
-    public void Move(Vector2 pos) {
-        this.pos = pos;
-        OnMove?.Invoke(pos);
-    }
-
-    public Vector2 Pos() {
-        return pos;
-    }
-
-    public void Selected(bool isSelected) {
-        if (this.isSelected != isSelected) {
-            OnSelected?.Invoke(isSelected);
-            this.isSelected = isSelected;
-        }
-    }
-
-    public bool IsSelected() {
-        return isSelected;
-    }
-
-    public VirtualPiece(string name = "", Vector2 pos = new Vector2()) {
-        this.name = name;
-        this.pos = pos;
-    }
-}