KcpMobilityFeatures

Versioned, dice-independent 27-column feature contract (kcp-mobility-27-v1).

Keeps KcpFeatures.extract as an unchanged 13-column prefix, followed by pseudo-legal move counts per moving piece type for the evaluation color (own_moves_p through own_moves_k), the same six for the opponent (opp_moves_p through opp_moves_k), and normalized piece diversity indices (own_pdi, opp_pdi).

All features are evaluated from the explicit perspective of color, independent of active color and dice.