docs: add reporting governance install guide

plugins/reporting-governance/README.md

@@ -103,6 +103,12 @@ npm --prefix plugins/reporting-governance test
 npm --prefix plugins/reporting-governance run smoke
 ```
 
+若你是另一個 AI agent，要照目前 package 真實邊界安裝/驗證，請直接讀：
+
+- `plugins/reporting-governance/INSTALL.md`
+
+這份文件會對齊目前 `exports`、smoke、tarball install test、以及「哪些不能假設」的邊界。
+
 #### 當作程式依賴使用
 
 優先只依賴：
@@ -180,6 +186,10 @@ Run tests:
 npm test
 ```
 
+For an exact AI-agent-facing install/verify flow, read:
+
+- `plugins/reporting-governance/INSTALL.md`
+
 ### Practical install/use guidance
 
 Use public exports only: