DeepSeek Harness Branch-Aware Conversation Difference Plugin

`dsh-fork-diff` is a read-only branch comparison plugin designed specifically for DeepSeek Harness, aimed at solving the difficulty of comparing long responses and tool trajectories after forking. It automatically discovers parent, child, and sibling branches, provides a side-by-side view that highlights differences in responses, tool calls, and results, and supports two-column desktop or single-column mobile layouts. The plugin is read-only throughout and does not modify any files, while offering pagination, quick alignment mode, and filtering capabilities. Users can select branches to compare from the session title bar, eliminating the need to manually process complex histories and enabling efficient identification of points of divergence.