Add space and infiltration evaluation

[KnightStackSys]

Adds a lightweight handcrafted Space/Infiltration term for 4PC Teams.

Evaluation

• Scores unique control of empty forward squares in each player's directional space zone.
• Uses a normalized forward-progress model so Red, Blue, Yellow, and Green are treated symmetrically.
• Rewards knights, bishops, rooks, and queens for physically penetrating deep into enemy-facing territory.
• Pawns are deliberately excluded from infiltration scoring so promotion potential can remain a separate pawn-specific evaluation term.
• Infiltration grows with depth but is capped so deep pieces cannot overwhelm material and mobility.
• The term is HCE-only; PhoenixNet behavior is unchanged.

Tunable parameters

• EvalSpaceControl = 1
• EvalInfiltrationKnight = 3
• EvalInfiltrationBishop = 3
• EvalInfiltrationRook = 2
• EvalInfiltrationQueen = 1

All parameters use the existing UCI tuning system, appear in tuneparams, and can be tuned with Tunex.

This branch is intentionally isolated for SPRT testing against main.