refactor

Features and purpose

既存コードを壊さずに段階的にリファクタする。責務分離、命名、境界（UI/ドメイン/データ層）整理、型の強化、重複排除、動作確認（lint/build/e2e）を伴う改善で使う。キーワード: refactor, cleanup, architecture, types

Quick start

Follow the repository instructions for this skill and your agent. Review the files and dependencies before adding it to your workflow.