dsh-archived-sessions: DSH Archived Session Management Plugin

DeepSeek Harness (DSH) archived sessions are typically stored as log files, making them cumbersome to manage. The `dsh-archived-sessions` plugin provides a unified management entry point through the UI, supporting session listing, content previewing, restoration, and permanent deletion. Released under the MIT license, the plugin quickly caches message counts and includes safety mechanisms such as protection against accidental deletion, blocking running sessions, and handling sub-sessions. Users must install pnpm and ensure that DSH is at version 0.1.5-rc.2 or later; after installing it with the `dsh plugin` command, restart to use it.