CI: build-only validation (no make/python/contexts); commit folded erudit.txt

- build.yaml dropped the release step whose ${{ github.* }} contexts failed the Gitea
  workflow compile (the run produced 0 jobs); it now inlines go run (no make dependency)
  and reads the committed dictprep/russian/erudit.txt (no python dependency).
- erudit.txt is scrabble.txt with Ё→Е folded (dictprep/fold_yo.py); it reproduces the
  canonical ru_erudit.dawg byte-for-byte. Release artifacts are published manually for now
  (see README).

Makefile

@@ -5,14 +5,14 @@
 # format and letter indexing match the running backend exactly (no index drift):
 #   en_sowpods.dawg  — English SOWPODS (Latin alphabet)
 #   ru_scrabble.dawg — Russian Scrabble nouns (Cyrillic, 33 letters)
-#   ru_erudit.dawg   — Эрудит (the same list with Ё→Е folded and de-duped)
+#   ru_erudit.dawg   — Эрудит (the Ё→Е folded + de-duped list, committed as russian/erudit.txt)
 #
-# The CI workflow packages dawg/*.dawg into a release artifact on a vX.Y.Z tag.
+# CI builds the DAWGs as a validation gate; release artifacts are published from this output
+# (see README.md). Regenerate russian/erudit.txt from scrabble.txt with dictprep/fold_yo.py.
 
 export GOPRIVATE := gitea.iliadenisov.ru/*
 
 GO        ?= go
-PYTHON    ?= python3
 DAWG_DIR  := dawg
 BUILDDICT := $(GO) run ./cmd/builddict
 
@@ -27,8 +27,7 @@ dawg-ru:
 	$(BUILDDICT) -dict dictprep/russian/scrabble.txt -alphabet russian -name ru_scrabble -out $(DAWG_DIR)
 
 dawg-erudit:
-	$(PYTHON) dictprep/fold_yo.py dictprep/russian/scrabble.txt > /tmp/ru_erudit_words.txt
-	$(BUILDDICT) -dict /tmp/ru_erudit_words.txt -alphabet russian -name ru_erudit -out $(DAWG_DIR)
+	$(BUILDDICT) -dict dictprep/russian/erudit.txt -alphabet russian -name ru_erudit -out $(DAWG_DIR)
 
 clean-dawg:
 	rm -f $(DAWG_DIR)/*.dawg