Add each department ministry as a feed

**Is your feature request related to a problem? Please describe.**
Each ministry seems to have its own news release feed, e.g. [Defence](https://www.canada.ca/en/news/advanced-news-search/news-results.html?_=1706187953394&typ=statements&dprtmnt=departmentnationaldefense&start=&end=), [Immigration](https://www.canada.ca/en/news/advanced-news-search/news-results.html?typ=newsreleases&dprtmnt=departmentofcitizenshipandimmigration&start=2015-01-01&end=)

We'd like to digest these feeds. For relevant entries, rather than having the AI try to match it to any promise, we should only match it to promises of that ministry. That should be more high signal.

**Describe the solution you'd like**
* See if there exists a high-signal feed for each ministry
* Ingest that
* Only attempt to match to relevant ministry

まず、Ruby API における既存の news-feed 取り込みと promise-matching のエントリポイントを特定します。各省庁についてシグナルの強いフィードを特定し、省庁のメタデータがどのように表現されているかを確認します。関連する省庁のフィードが取り込まれ、エントリが同じ省庁の promise に対してのみマッチングされれば完了です。

索引モデルが issue の本文から書いたものです。