DeepSeek Harness Plugin dsh-zcode-rewind: Per-Tool-Call Workspace Checkpoints

`dsh-zcode-rewind` is a workflow plugin for DeepSeek Harness designed to address the limitations of existing rollback tools, which cannot capture the side effects of Shell commands and suffer from coarse rollback granularity. This plugin captures file changes and Shell operations at the tool-call level, stores blobs using SHA-256 content-addressed storage, and supports fine-grained checkpoint creation, line-level diff preview, rollback, and deduplication management. Users can manage checkpoints through specific commands and control storage quotas and capture modes via configuration options, enabling highly reliable state rollback in agent development.