Fix asymmetric evaluation terms on non-8x8 boards

[Belzedar94]

Summary

• derive outpost ranks from the current board size so minor-piece bonuses remain color-symmetric
• use relative ranks for pawn double-push threat generation to respect variant dimensions
• build the space evaluation mask from the actual board area to keep the bonus symmetric across colors

Testing

• make build -j2

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https://chatgpt.com/codex/tasks/task_e_68d12ea8b52c8322b0f20bac720c2bf6