add custom chess engine

native/chess_engine/src/uci.h

@@ -0,0 +1,19 @@
+// Conversions between moves and UCI long-algebraic strings ("e2e4", "e7e8q").
+// move_from_uci resolves the move's flag (castling / en passant / promotion)
+// against the given position.
+#ifndef CHESS_UCI_H
+#define CHESS_UCI_H
+
+#include "position.h"
+
+#include <string>
+#include <string_view>
+
+namespace chess {
+
+std::string move_to_uci(Move m);
+Move        move_from_uci(const Position& pos, std::string_view uci);
+
+} // namespace chess
+
+#endif // CHESS_UCI_H