docs: extract guide design into reusable skills

README.md

@@ -41,6 +41,7 @@ npm run verify
 - `hands-on/starter/` — dependency-free Tiny Tasks exercise
 - `hands-on/rules/` — dependency-free Guardrails lab; toggles rule sources into the prompt
 - `rules/` — bilingual case study of skills, CLI ratchets, Husky, and PR review
+- `skills/` — reusable design and rules-case-study skills extracted from this implementation
 - `GATES.md` — acceptance ledger for the project
 
 ## Publishing
@@ -74,3 +75,8 @@ skills, machine-readable repo ledgers, a UI contract ratchet, lint-staged,
 Husky, commitlint, specialist verifier agents, and PR review reinforce one
 another. Every example links to its source file in Gitea, and the page includes
 a copy-ready prompt for mapping the same layers in another repository.
+
+The implementation patterns are also packaged as project-local skills in
+[skills/](skills/README.md). Use `editorial-playbook` when adding chapters or
+sections, and `rules-case-study` when turning repository controls into a
+source-linked teaching page.