sashite-pnn 2.0.0

PNN (Piece Name Notation) extends PIN to provide style-aware piece representation in abstract strategy board games. This gem implements the PNN Specification v1.0.0 with a modern Ruby interface featuring immutable piece objects and functional programming principles. PNN adds derivation markers to PIN that distinguish pieces by their style origin, enabling cross-style game scenarios and piece origin tracking. Represents all four Game Protocol piece attributes with full PIN backward compatibility. Perfect for game engines, cross-tradition tournaments, and hybrid board game environments.