DSH Plugin: dsh-archive-session (Browse and Clean Up Archived Sessions)

Although DSH officially supports session archiving, it does not provide a way to manage archived sessions. This plugin fills that operational gap by supporting browsing, closing (without a restart), unarchiving, and deleting archived sessions. Installation requires the `dsh plugin` command and a service restart. It can be used through Agent tools, and it also provides an HTTP API for automated calls. Note that a session must be closed before deletion, and only the JSONL persistence backend is supported.