update-changelog

name	update-changelog
description	Add an entry to CHANGELOG.md after implementing a feature, fix, or other notable change in this repo. Use when the user asks to update the changelog, or right after finishing a code change that should be logged.

Update Changelog

Edit CHANGELOG.md at repo root after implementing a change.

Steps

1. Open CHANGELOG.md.
2. Add the entry under ## [Unreleased] (create this section right after the intro lines if missing).
3. Under [Unreleased], use one of these exact Japanese category subheadings:
   • ### 追加 - new feature
   • ### 修正 - fix / change to existing behavior
   • ### その他 - other (docs, chore, refactor)
4. If the category subheading already exists under [Unreleased], append a bullet to it instead of duplicating the heading.
5. Write one bullet per change, in Japanese, matching the terse style of existing entries (e.g. 〜を追加, 〜を修正), no trailing period.
6. For a sub-detail, nest a bullet with 2-space indent under the parent bullet.
7. Do NOT bump the version number or add a new ## [x.y.z] - date heading unless the user explicitly asks to release/bump version.
8. Never edit already-released version sections.

Format reference

## [Unreleased]

### 追加

- 新機能の説明

### 修正

- 修正内容の説明