docs(i18n): commit the pipeline translation prompt as a repo asset

自动翻译流水线的 prompt 模板进仓（docs/i18n/translation-prompt.md）：
占位符契约（source_lang/target_lang/terminology 三个，旧 %% 分段协议
废弃）+ 逐字模板正文（三段 XML 输出、分类自审、8 组正误例）。列入
配对排除清单；skill 与流水线自此共用同一套规则文件。

docs/i18n/README.md

@@ -42,6 +42,7 @@ The gate's limit, stated plainly: **a green gate means the pair was confirmed co
 - `docs/cordis-catalog/`, `docs/tool-catalog/`, `docs/module-graph.md` — generated files; their generators emit English only today, so a hand-written translation would go stale on every regeneration. The planned follow-up is to teach the generators to emit Chinese alongside English, at which point these leave the exclusion list.
 - `docs/AGENTS.md` — agent instructions, maintained in English only like the root `AGENTS.md`.
 - `docs/i18n/terminology.md` and [style-samples.md](style-samples.md) — both are bilingual by construction.
+- [translation-prompt.md](translation-prompt.md) — the automated pipeline's prompt template; its body is machine-consumed verbatim, so a paired translation would change pipeline behavior.
 
 **Rollout**: new documents don't wait for a batch — a date-named document (`yyyy-mm-dd-*.md`, i.e. an RFC) dated on or after the manifest's `requiredSince` cutoff must merge with its pair, so everything new is bilingual from birth. Files dated before the cutoff are the grandfathered backlog by definition — including files created on the cutoff's eve — and a document's filename date is its first-proposed date per the RFC convention, so backdating past the cutoff is a review-visible violation, not a loophole. For the back-catalog, the `required` list in the manifest is the enforcement frontier, not the goal. The goal is full bilingual coverage of the scope. Pairs land in reviewable batches (core entry docs, cookbook, RFCs, postmortems, …); each merged batch adds its files to `required`, so the gate ratchets forward and never regresses. Documents not yet in `required` are backlog — visible in `--list` — but any pair that already exists is held to the full contract regardless of the list. Pairing a document is a commitment: every later edit to either side must carry the counterpart along, so grow the frontier at the pace translation review is actually resourced, not ahead of it.