compact-region: Local compression of consecutive rounds in DSH

compact-region is a DSH Web plugin maintained by Asdika-36086 that summarizes consecutive visible turns in a conversation into an editable checkpoint card using the current session model. Once applied, the original text remains in the session logs but no longer occupies model context. Based on the official README, this article covers installation (via plugin manager or `dsh plugin install`), selection rules, typical workflows, and summary privacy, archiving, and known limitations. It is suitable for organizing long session contexts in DSH 0.2.x.