dsh-session-categories: Adding Manageable Session Categorization to DeepSeek Harness

dsh-session-categories is a DSH plugin developed by ht719, designed to address the issue of chaotic web session management. It provides an independent, user-manageable category tree for each Workspace, supporting the creation, renaming, moving, and archiving of categories and sessions, and allows for hierarchical adjustment through drag-and-drop operations. This plugin is suitable for unmodified DSH installations and requires the current pre-release plugin API. During installation, regular users can enable it by running `dsh plugin --profile web add dsh-session-categories`. Typical usage includes creating top-level or subcategories in the sidebar, assigning new or existing sessions to corresponding categories, thereby organizing sessions hierarchically. It should be noted that this plugin targets the pre-release API, and