feat(doc-review, learnings-researcher): tiers, chain grouping, rewrite (#601)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/solutions/best-practices/codex-delegation-best-practices-2026-04-01.md

@@ -3,7 +3,7 @@ title: "Codex Delegation Best Practices"
 date: 2026-04-01
 category: best-practices
 module: "Codex delegation / skill design"
-problem_type: best_practice
+problem_type: convention
 component: tooling
 severity: medium
 applies_when: