docs: EN source-of-truth workflow (en2ru + DOCSTRAT)

- en2ru.py: EN markdown -> Russian via Ollama translategemma-4b (tag: translategemma:latest)
  strips code-fence artifacts, prints jargon-review hints to stderr
- DOCSTRAT.md: rule -- EN canonical source, RU for comprehension only,
  never edit on drifted Russian (dedup/receipt mistranslation guard)
- ROADMAP.ru.md: sample RU generated from EN source
- AGENTS.md: section 8 documenting the EN-first workflow

AGENTS.md

@@ -134,3 +134,14 @@ A **gap** is a question you know you cannot answer yet. Manage them, don't just
 - If the question turned out irrelevant → `status='dismissed'` (prefer this over deleting).
 - Raise `priority` when the user asks about the topic; lower it when it stops mattering.
 - Keep questions **specific and answerable** ("How does HNSW build its graph?" not "HNSW").
+
+## 8. Documentation language (English source of truth)
+
+All docs (`*.md`) are written in **English = canonical source of truth**. Russian
+(`*.ru.md`) is generated for quick comprehension only; terminology may drift and must
+NEVER be used as the editing basis (editing on drifted Russian breaks intent).
+
+Workflow: write/edit EN → `python3 en2ru.py file.md` → `file.ru.md`. See
+[`DOCSTRAT.md`](./DOCSTRAT.md). `translategemma:latest` renders clean orthography but
+mishandles jargon (`dedup`→«дублирование», `receipt`→«результат»), so review the
+stderr hints; keep unsure terms in Latin.