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).

README.md

@@ -19,20 +19,23 @@ byte-identical to the solver's committed test fixtures.
 | --- | --- | --- |
 | `en_sowpods.dawg` | English (SOWPODS) | `dictionaries/english/sowpods.txt` |
 | `ru_scrabble.dawg` | Russian Scrabble | `dictprep/russian/scrabble.txt` |
-| `ru_erudit.dawg` | Эрудит | the Russian list with Ё→Е folded (`dictprep/fold_yo.py`) |
+| `ru_erudit.dawg` | Эрудит | `dictprep/russian/erudit.txt` (Ё→Е folded `scrabble.txt`, via `dictprep/fold_yo.py`) |
 
-The CI (`.gitea/workflows/build.yaml`) builds them on every push/PR and, on a `vX.Y.Z` tag,
-packages them flat into `scrabble-dawg-<tag>.tar.gz` and attaches it to the Gitea release. The
-backend deploy unpacks that tarball into `BACKEND_DICT_DIR`; **one semver label versions the
-whole set** (additive — a new version is a new release, never breaking a running backend).
+The CI (`.gitea/workflows/build.yaml`) rebuilds them on every push/PR as a validation gate
+(inlined `go run`, no `make`/`python` needed on the runner). Release artifacts are published per
+version (see **Release** below): the three DAWGs packaged flat into `scrabble-dawg-<tag>.tar.gz`
+and attached to the Gitea release for the `vX.Y.Z` tag. The backend deploy unpacks that tarball
+into `BACKEND_DICT_DIR`; **one semver label versions the whole set** (additive — a new version is
+a new release, never breaking a running backend).
 
 ## Sources / provenance
 
 - **English:** `dictionaries/english/sowpods.txt`, vendored from
   [`kamilmielnik/scrabble-dictionaries`](https://github.com/kamilmielnik/scrabble-dictionaries).
 - **Russian:** `dictprep/russian/scrabble.txt`, derived from the Russian academic orthographic
-  dictionary by the tooling under `dictprep/` (see `dictprep/README.md`). Only the prepared word
-  list is vendored; the heavy upstream source (the orfo PDF/text) is not.
+  dictionary by the tooling under `dictprep/` (see `dictprep/README.md`); `dictprep/russian/erudit.txt`
+  is its Ё→Е folded form (`dictprep/fold_yo.py`). Only the prepared word lists are vendored; the
+  heavy upstream source (the orfo PDF/text) is not.
 
 ## Build
 
@@ -41,4 +44,20 @@ make dawg     # -> dawg/{en_sowpods,ru_scrabble,ru_erudit}.dawg
 ```
 
 Requires Go (module deps fetched with `GOPRIVATE=gitea.iliadenisov.ru/*`, exported by the
-Makefile) and `python3` (for the Ё→Е fold).
+Makefile). No `python` is needed for the build — the Ё→Е fold is committed as `erudit.txt`;
+regenerate it with `python3 dictprep/fold_yo.py dictprep/russian/scrabble.txt > dictprep/russian/erudit.txt`.
+
+## Release
+
+CI builds and validates the DAWGs but does not upload them (the release upload needs a write
+token, kept out of CI for now — a future enhancement). To publish a version, tag it and attach
+the artifact to its Gitea release:
+
+```sh
+make dawg
+tar czf scrabble-dawg-vX.Y.Z.tar.gz -C dawg en_sowpods.dawg ru_scrabble.dawg ru_erudit.dawg
+# create the Gitea release for tag vX.Y.Z and upload scrabble-dawg-vX.Y.Z.tar.gz as an asset
+```
+
+The backend consumes it at
+`https://gitea.iliadenisov.ru/developer/scrabble-dictionary/releases/download/vX.Y.Z/scrabble-dawg-vX.Y.Z.tar.gz`.