movePiece method
Moves a piece on the board without validation.
Implementation
bool movePiece(Position from, Position to) {
ChessPiece? piece = getPiece(from);
if (piece == null) return false;
// Move the piece to the new position
board[to.row][to.col] = piece;
board[from.row][from.col] = null;
return true;
}