dsh-branch-workspace-folders: DSH Sidebar Session Tree Refactoring Plugin

The DeepSeek Harness sidebar plugin addresses hierarchy confusion caused by a growing number of sessions by building a universal fork tree that groups forked sessions under their root sessions. It supports dual-track indentation decoupling, collapse-state bubbling, and a physical cascading deletion engine, and exposes a REST API for health checks, archive queries, and deletion operations. The plugin employs a heap allocation algorithm to ensure reliability, supports tri-state archive filtering and DSH official slot integration, and is suitable for users who need fine-grained management of large session volumes and thorough log cleanup. Installation from source or via a package manager is recommended.