dictprep: Russian orthographic dictionary → Scrabble noun pipeline

Build a committed Russian common-noun word list (dictprep/russian/scrabble.txt)
from the RAN orthographic dictionary, for the Эрудит ruleset.

- Stage 1 (Go, dictprep/ruwords): orfo_dict_2025.txt -> all.txt; extracts
  headwords, reconstructs "ед." singulars (suppressing plurals), pairs "и" variants.
- Stage 2 (Python brain, dictprep/ru_stage2.py): OpenCorpora (mawo-pymorphy3) +
  libmorph + orthographic notes select common nouns (nom. sing.); --trace explains
  a word's fate, --dump writes the in-memory buckets.
- libmorph C++ bridge (libmorph_check.cpp); manual_confirm.txt is merged in.
- orfo_dict_2025.txt is the committed pdftotext source of truth.
- See dictprep/README.md for methodology and reproducibility.

dictprep/libmorph_check.cpp

@@ -0,0 +1,47 @@
+// libmorph_check: a thin stdin->stdout bridge to the libmorph Russian morphological
+// analyser, for use by the Stage-2 classifier (scripts/ru_stage2.py).
+//
+// Reads one word per line (bytes are passed through verbatim — the caller encodes to
+// the code page the libmorph char interface expects, CP1251). For each word it writes
+// a line:
+//
+//     <known>\t<pos>:<lemma>\t<pos>:<lemma>...
+//
+// where <known> is CheckWord's result (1 = in the dictionary, 0 = not), and each
+// following field is one lexeme: its part of speech (wdInfo & 0x3f) and lemma.
+//
+// Build: g++ -std=c++17 -O2 scripts/libmorph_check.cpp -lmorphrus -lmoonycode -o libmorph_check
+#include <libmorph/rus.h>
+#include <libmorph/api.hpp>
+#include <cstdio>
+#include <iostream>
+#include <string>
+
+int main(int argc, char** argv) {
+  // The factory key selects the code page: "libmorph.api.v4:<charset>". Use the
+  // UTF-8 instance so words pass through verbatim. IMlmaMbXX only adds non-virtual
+  // convenience wrappers over IMlmaMb, so the filled pointer can be used as such.
+  const char* key = argc > 1 ? argv[1] : "libmorph.api.v4:utf-8";
+  IMlmaMbXX* mlma = nullptr;
+  int rc = mlmaruGetAPI(key, (void**)&mlma);
+  if (mlma == nullptr) {
+    std::fprintf(stderr, "libmorph_check: GetAPI('%s') failed, rc=%d\n", key, rc);
+    return 1;
+  }
+  std::string line;
+  while (std::getline(std::cin, line)) {
+    if (!line.empty() && line.back() == '\r') line.pop_back();
+    IMlmaMbXX::inword w(line.c_str(), line.size());
+    int known = mlma->CheckWord(w, sfIgnoreCapitals);
+    std::cout << known;
+    try {
+      for (auto& lx : mlma->Lemmatize(w, sfIgnoreCapitals)) {
+        unsigned pos = lx.ngrams > 0 ? (lx.pgrams[0].wdInfo & 0x3f) : 0xffu;
+        std::cout << '\t' << pos << ':' << (lx.plemma ? lx.plemma : "");
+      }
+    } catch (...) {
+    }
+    std::cout << '\n';
+  }
+  return 0;
+}