DeepSeek Harness Session Archive Button Plugin

The `dsh-archive-button` plugin is an automated session cleanup tool for DeepSeek Harness (DSH), designed to address the issue of historical sessions taking up storage space. Located in the sidebar, it provides a "dry run" prescan for sessions idle for more than 3 days and a secondary confirmation before packaging, creating a zip backup and deleting the original files to ensure data safety. The project has now been archived in the `dsh-chrome-suite` repository and is retained for historical reference only.