DeepSeek Harness Plugin: dsh-pr-description

`dsh-pr-description` is a native plugin for DeepSeek Harness that uses deterministic rules to automatically generate PR descriptions, titles, and self-review checklists compliant with the Conventional Commits specification. By analyzing Git diffs, it classifies changes and extracts symbols to assemble a five-part description document, and supports interactive confirmation or direct PR submission. It runs with fixed parameters to ensure reproducible and controllable results, addresses the pain point of manually writing documentation, and is suitable for CI or local workflows.