dsh-rewind: A Rollback Tool for Directory Operations

`dsh-rewind` is a DSH plugin that provides "time travel" capabilities specifically for agent development. It does not depend on Git and supports uncommitted changes, non-repository directories, and arbitrary file snapshots. Through content addressing and undo mechanisms, users can safely perform destructive operations or rollbacks using commands such as `rewind snap`, `undo`, and `rewind exec`. The tool ensures the reversibility and atomicity of directory state, offering a reliable "antidote" for agent development.