Extract `changelog-check` to separate action

The `changelog-check` workflow helps us ensure that changelogs are updated alongside changes in polyrepos and monorepos.

Currently, when we make use of this workflow in other repos we need to pin to a specific commit ID. This is cumbersome because it means that if we want to make a change to the workflow we now need to go through each repo by hand and update the commit ID.

If we extracted this workflow to an action, we could start using version strings such as `v1`. As long as new changes were backward compatible they would automatically get propagated to all of the repos.

首先定位現有的 changelog-check workflow，並檢視其他 repository 如何使用它。將其提取為具版本的 GitHub Action，更新使用模型以支援 v1-style 參照，並驗證 changelog 檢查在 polyrepo 和 monorepo 中仍然有效。

由索引模型根據 Issue 內容生成。