PortShapeConverter class

A JSON converter for PortShape class.

This converter serializes PortShape objects to JSON using their toJson method, and deserializes JSON maps back to PortShape objects using the factory constructor.

Example JSON representation:

{
  "type": "circle"
}

For shapes with orientation:

{
  "type": "triangle",
  "orientation": "right"
}

Usage with json_serializable:

@JsonSerializable()
class Port {
  @PortShapeConverter()
  final PortShape shape;

  Port(this.shape);
}