Rarog 2.2.0

Rarog 2.2.0 fits the engine's evaluation to data. Phase 3 rebuilt the eval as a
fully parameterised, trace-instrumented function (every term seeded inert, so the
rewrite was bench-identical), and Phase 4 then fit that enlarged eval to a 2.19M-position
self-play set — a staged offline Texel tune, each stage SPRT-gated. This is the single
largest strength jump in the project so far.

Against an external field, Rarog 2.2.0 plays roughly +240 Elo stronger than 2.1.0,
placing it at approximately 3000 CCRL.

Added

• King-danger evaluation — a single danger accumulator (attacker units, safe checks,
  weak king-ring, king flank, pawnless flank, queen relief) feeding a non-linear
  danger→score curve.
• Threat evaluation v2 — per-victim threat-by-minor/rook tables, a refined
  weakly-defended-piece term (which retired the old flat hanging penalty), safe-pawn-push
  threats, and weak-piece / restricted-square terms.
• Per-count mobility tables for knight/bishop/rook/queen, replacing the flat per-move bonus.
• Expanded pawn-structure & passed-pawn evaluation — rank-scaled connected pawns,
  supported / free-stop / safe-stop / candidate passers, blocked-passer and ideal-blockader
  terms, plus assorted positional terms (outposts, rook files/7th, bishop long-diagonal,
  space, king-centrality danger).
• Material-imbalance evaluation — symmetric per-piece-pair quadratic.
• Exact endgame knowledge — a KPK bitbase plus scale-factor handling for known
  drawish/won material (KBNK mating drive, wrong-corner bishop, opposite-coloured bishops,
  bare-rook and insufficient-material draws).
• Eval cache + lazy-eval fast path — a whole-position cache and a fast path that skips
  the expensive positional terms when the material+PST margin is already decisive.
• Offline Texel-tuning tooling under tools/texel-tuner/ and tools/texel/.

Changed

• Material values and piece-square tables refit against the now-complete term set
  (classical piece ratios preserved).
• The bench fingerprint changed as eval behaviour changed.

Binaries

Use the most advanced asset your CPU supports (pext for BMI2/PEXT CPUs, avx2 for
x86-64-v3, plain x86-64 for maximum compatibility, arm64 for ARM). Binaries are built
with portable CPU targets and attached automatically below.

Full changelog: v2.1.0...v2.2.0