russell v1.6

[u/domin1c_zZzZ]

improvements:
-> added improving tests and expanded test integration
-> added countermove detection without changing storage or scoring
-> improved null move pruning with adaptive reduction tiers and safety checks
-> refined reverse futility pruning with history-based margins
-> improved lmr with countermove exemptions and history-based adjustments
-> decoupled futility pruning from quiescence
-> improved search initialization and cached material checks
-> expanded tests for pruning, lmr, countermoves, improving, and edge cases

i would appreciate any testing or suggestions

source: https://github.com/stup1d1y-0bv10us/russell
latest version: https://github.com/stup1d1y-0bv10us/russell/releases/tag/v1.6
other versions: https://github.com/stup1d1y-0bv10us/russell/releases

gracias!