docs(i18n): core-data-structures and postmortem batch — 22 bilingual pairs

core-data-structures 18 篇（core.md 因超长仍在产出、随后补）、
postmortem 3 篇与 RFC 前门 README 配对；流水线 + 二遍校验产出。
生成文件 docs/rfc/INDEX.md（gen-rfc-index 产物）列入排除。中文侧
页内锚点统一指向英文侧锚名，满足配对门禁的链接目标一致规则。

docs/core-data-structures/llm-streaming.md

@@ -1,5 +1,7 @@
 # LLM Streaming
 
+English | [中文](llm-streaming.zh.md)
+
 The wire-level streaming vocabulary of [dsh-llm](../../packages/llm/llm). [core.md](core.md) introduces `StreamChunk`, `Message`, and `ContentBlock`; this page owns the full chunk protocol, the adapter contract every adapter must obey, and the shared assembler.
 
 Source: [`packages/llm/llm/src/types.ts`](../../packages/llm/llm/src/types.ts)