dsh-session-git: DeepSeek Harness Conversation Lineage and Branch Management Plugin

dsh-session-git is a DeepSeek Harness plugin that addresses the limitation of the official fork, which only supports branching from the latest turn. It allows users to branch from any previous turn and displays a session family tree in the child session header. The plugin does not modify source sessions or workspace files; it focuses exclusively on visualizing and navigating session lineage and requires use with Web mode.