chore: add gstack skill routing rules to CLAUDE.md

CLAUDE.md

@@ -90,3 +90,23 @@ The production-style stack lives in `greenlns-landing/docker-compose.yml` and in
 - Nested plant metadata such as `categories` and `careInfo` uses `JSONB`.
 - Billing idempotency responses also use `JSONB`.
 - SQL placeholders use PostgreSQL syntax: `$1`, `$2`, ...
+
+## Skill routing
+
+When the user's request matches an available skill, ALWAYS invoke it using the Skill
+tool as your FIRST action. Do NOT answer directly, do NOT use other tools first.
+The skill has specialized workflows that produce better results than ad-hoc answers.
+
+Key routing rules:
+- Product ideas, "is this worth building", brainstorming -> invoke office-hours
+- Bugs, errors, "why is this broken", 500 errors -> invoke investigate
+- Ship, deploy, push, create PR -> invoke ship
+- QA, test the site, find bugs -> invoke qa
+- Code review, check my diff -> invoke review
+- Update docs after shipping -> invoke document-release
+- Weekly retro -> invoke retro
+- Design system, brand -> invoke design-consultation
+- Visual audit, design polish -> invoke design-review
+- Architecture review -> invoke plan-eng-review
+- Save progress, checkpoint, resume -> invoke checkpoint
+- Code quality, health check -> invoke health