dsh-session-mover: Drag sessions to other workspaces in DSH Web GUI

dsh-session-mover is an MIT-licensed plugin for DeepSeek Harness designed to streamline the organization of sessions across workspaces. The plugin supports directly dragging session rows with full history to a target workspace header, effectively achieving the semantics of "cloning a new session and archiving the original," without requiring additional panels or buttons. Its core advantage lies in preserving full context and avoiding manual copy-paste; if a currently open session is moved, the user is automatically redirected to the new copy. Technically, the plugin leverages the official sidebar's drag-and-drop mechanism to locate the target workspace via semantic attributes and invokes the host API to perform the steps of reading source logs, creating a new session in the target workspace, persisting and associating it, and finally archiving the source session. Due to limitations in the platform's storage layer, in-place migration of session IDs is impossible, so the copy-and-archive approach is adopted. This plugin is suitable for users needing flexible adjustments.