Add stellarwp/foundation-wpcli link and update AGENTS.md

Author: defunctl

AGENTS.md

@@ -9,6 +9,7 @@ Initial packages:
 - `stellarwp/foundation-container`
 - `stellarwp/foundation-log`
 - `stellarwp/foundation-pipeline`
+- `stellarwp/foundation-wpcli`
 
 ## Namespaces
 
@@ -67,6 +68,8 @@ Each split package should include:
 - `.gitignore`
 - `.github/workflows/close-pull-request.yml`
 
+When adding a new split package, add its `stellarwp/foundation-<package>` repository link to the root `README.md` repositories list.
+
 Each split package `README.md` must include this warning immediately after the package heading:
 
 ```markdown

README.md

@@ -9,6 +9,7 @@ Foundation is a StellarWP Composer monorepo for reusable PHP packages intended f
 - [stellarwp/foundation-container](https://github.com/stellarwp/foundation-container)
 - [stellarwp/foundation-pipeline](https://github.com/stellarwp/foundation-pipeline)
 - [stellarwp/foundation-log](https://github.com/stellarwp/foundation-log)
+- [stellarwp/foundation-wpcli](https://github.com/stellarwp/foundation-wpcli)
 
 ## Installation