docs(zh-CN): unify cross-reference style in ARM64 section

Audited README.zh-CN.md against sparanoid/chinese-copywriting-guidelines.
The whole file already follows the CJK<->Latin spacing rule and uses
full-width punctuation correctly — automated scan returns zero
violations. The only inconsistency was the new "Linux ARM64" block
referencing the source-install section as `[「从源码安装」]`, while every
other cross-reference in this README uses the bare-link style. Drop the
`「」` brackets so it matches.

(Heti / sivan/heti is a runtime CSS library — it can't apply to README
rendering on GitHub, but is worth wiring up if we ever publish a docs
site.)

https://claude.ai/code/session_01Fg1FKMtDxVnC4pp6bNBRCS

README.zh-CN.md

@@ -48,7 +48,7 @@ deepseek
 
 预构建二进制覆盖 **Linux x64**、**Linux ARM64**（v0.8.8 起）、**macOS x64**、
 **macOS ARM64**、**Windows x64**。其他平台（musl、riscv64、FreeBSD 等）请见
-下方[「从源码安装」](#从源码安装)，或参考完整的
+下方的 [从源码安装](#从源码安装) 章节，或参考完整的
 [docs/INSTALL.md](docs/INSTALL.md)。
 
 首次启动时会提示输入 [DeepSeek API key](https://platform.deepseek.com/api_keys)。也可以提前配置：