Chess: Add castling to possible moves detection

src/chess.lua

@@ -589,6 +589,9 @@ local function get_theoretical_moves_from(meta, board, from_idx)
 
 		-- KING
 		elseif piece == "king" then
+			if attacked(color, xy_to_index(to_x, to_y), board) then
+				moves[to_idx] = nil
+			else
 				local dx = from_x - to_x
 				local dy = from_y - to_y
 
@@ -601,11 +604,11 @@ local function get_theoretical_moves_from(meta, board, from_idx)
 				end
 
 				if dx > 1 or dy > 1 then
+					local cc = can_castle(meta, board, "board", from_idx, to_idx)
+					if not cc then
 						moves[to_idx] = nil
 					end
-
-			if attacked(color, xy_to_index(to_x, to_y), board) then
-				moves[to_idx] = nil
+				end
 			end
 		end
 	end