dsh-workspace-api: Enterprise Knowledge Q&A and File Management API

`dsh-workspace-api` is an enterprise knowledge Q&A plugin for DeepSeek Harness (DSH). It leverages AI agents' on-the-fly retrieval capability to turn enterprise documents into a conversational bot without prebuilding indexes. The plugin supports natural-language Q&A with citations via an HTTP API and provides an interface for file directory management. Installation is performed via the CLI, and by default it listens locally only. Configuration requires setting the document root directory and an access token to ensure security. It is suitable for knowledge-base Q&A at the scale of tens of documents; scanned PDFs should be OCR-processed first.