dsh-vault: Encrypted Configuration Backups in Private GitHub Repositories

`dsh-vault` is a DeepSeek Harness (DSH) plugin designed to securely encrypt and sync local configuration to a private GitHub repository. It uses scrypt + AES-256-GCM to encrypt configuration (including keys), plugin manifests, and credentials, and supports backup, restore, and management through the `/vault` command. It has zero dependencies and supports interactive configuration, but only the latest snapshot is retained per machine, and it does not support migration of `.env` files, session history, or absolute-path dependencies. If the password is lost, the data cannot be recovered.