Fix `Rectangle::Contains` bounds check

Source/engine/rectangle.hpp

@@ -12,9 +12,9 @@ struct Rectangle {
 	constexpr bool Contains(Point point) const
 	{
 		return point.x >= this->position.x
-		    && point.x <= (this->position.x + this->size.width)
+		    && point.x < (this->position.x + this->size.width)
 		    && point.y >= this->position.y
-		    && point.y <= (this->position.y + this->size.height);
+		    && point.y < (this->position.y + this->size.height);
 	}
 };