docs: research display control scope

README.md

@@ -172,6 +172,7 @@ Capability detection is done at runtime — on unsupported hardware, commands te
 
 - [中文项目文档](docs/README.zh-CN.md) — vision, research notes, and roadmap (Chinese)
 - [Fan profile cookbook](docs/fan-profiles.md) — design, apply, verify, and troubleshoot custom fan curves (Chinese)
+- [Display control research](docs/research-display-control.md) — scope, risks, and staged command design for future external-display hardware control (Chinese)
 - [Architecture & design](docs/design.md) (Chinese)
 - [Field notes: M4 Mac mini](docs/field-notes-m4-mini.md) — real-hardware findings, including SMC asynchronous-write behavior (Chinese)
 

docs/README.zh-CN.md

@@ -164,6 +164,7 @@ $ smctl alert test cpu-hot    # 立即触发动作，验证 webhook/脚本是否
 
 - [架构与技术设计](design.md)
 - [风扇曲线设计教程](fan-profiles.md)
+- [显示器控制调研](research-display-control.md)——外接显示器硬件控制、DDC/CI、EDID、诊断面和分阶段命令设计
 - [真机实测笔记：M4 Mac mini](field-notes-m4-mini.md)——含 SMC 异步写入等一手发现
 - [项目调研与规划笔记](project-notes.zh-CN.md)