Phase A NNUE: feature-indexing spec, annotation/training pipeline, dump nnuefeatures

Builds out the NNUE Phase A prototype per docs/NNUE.md:

- src/nnuefeatures.c: standalone HalfKAv2_hm feature-index reference
  implementation (new `dump nnuefeatures` command), sourced from
  Stockfish's half_ka_v2_hm.{h,cpp} (sf_16 tag), including the 0x88->64
  square conversion typhoon's own board representation needs.
- annotate_pgns/: sharded TWIC/self-play annotation harness
  (annotate.py), position extraction, quiet-position filtering (flat
  and game-shaped, plus an upstream --prefilter-quiet option),
  train/holdout game-level stratified split, WDL-sigmoid K fitting,
  the Python HalfKAv2_hm reference encoder (nnue_feature_spec.py) and
  its bit-for-bit cross-checker against the C side
  (cross_check_features.py), and a first PyTorch training pipeline
  (nnue_model.py, nnue_train.py, build_training_tensors.py) -- a
  256x2-32-32-1-ish net trained locally on CPU against ~1.85M quiet
  TWIC positions as a pipeline/framework validation pass.
- Finish an in-progress InitMagic/InitLMRTable/InitEval ->
  InitializeBitboardMagic/InitializeLMRTable/InitializeEval rename:
  chess.h's prototypes hadn't been updated to match the already-renamed
  definitions/call sites, leaving 4 implicit-function-declaration
  warnings.
- tests/arasan.epd: new curated EPD suite.
- docs/: add the project's design docs (previously untracked).

Co-Authored-By: Claude Sonnet 5 <[email protected]>

1 files changed, 13 insertions, 2 deletions

diff --git a/src/command.c b/src/command.c
index b30de2b..715c989 100644
--- a/src/command.c
+++ b/src/command.c
@@ -313,6 +313,7 @@ Routine description:
         dump sizes
         dump eval [optional coor]
         dump evaldna
+        dump nnuefeatures
 
         This command is used to dump internal information to the
         stdout.  
@@ -335,6 +336,12 @@ Routine description:
         provided then the eval terms DIRECTLY affected by the piece at
         the supplied coordinate is produced.  Note: to use dump eval
         the engine must have been built with -DEVAL_DUMP.
+
+        When used with the 'nnuefeatures' argument, prints the sorted
+        set of active HalfKAv2_hm feature indices for both
+        perspectives at the current position -- see nnuefeatures.c
+        and docs/NNUE.md. Reference-implementation-only, not wired
+        into eval/search.
     
 Parameters:
 
@@ -376,12 +383,16 @@ Return value:
     {
         DumpSizes();
     }
-    else if (!STRCMPI(argv[1], "evaldna")) 
+    else if (!STRCMPI(argv[1], "evaldna"))
     {
         char *p = ExportEvalDNA();
         Trace("EvalDNA: %s\n", p);
         free(p);
     }
+    else if (!STRCMPI(argv[1], "nnuefeatures"))
+    {
+        DumpNnueFeatures(pos);
+    }
 #ifdef EVAL_DUMP
     else if (!STRCMPI(argv[1], "eval"))
     {
@@ -737,7 +748,7 @@ Return value:
             // ROOK_ON_HALF_OPEN_WITH_FRIEND, kept static rather than
             // rebuilt every _EvalRook call since it's speed-critical
             // code -- a DNA reload has to explicitly refresh it.
-            InitEval();
+            InitializeEval();
 
             // EvalCommand's persistent SEARCHER_THREAD_CONTEXT keeps
             // its embedded eval hash alive across calls for speed; a