dsh-sessions-manager: DeepSeek Harness Session Management Panel Plugin

`dsh-sessions-manager` is a client plugin for DeepSeek Harness (DSH), maintained by TOBYCAI, designed to address the pain point of fragmented session management. It provides a unified panel in Settings, supporting filtering and sorting by workspace and tags, along with cross-workspace drag-and-drop, bulk operations, trash management, session detail analysis (including tool-call statistics and lineage), and storage usage analysis. Sidebar enhancements support status dot display and quick menus. The plugin is compatible with DSH 0.1.5+ and can be installed via command line.