dsh-project-progress: Project Progress Documentation Shared in the Workspace

dsh-project-progress is a DeepSeek Harness plugin that creates a shared `PROGRESS.md` document in the DSH workspace to manage project status and share context across sessions. The document is divided into two sections—project profile and progress timeline—and supports read/write operations through three tools: `project_update`, `project_facts`, and `project_status`. The plugin runs locally with no network calls, automatically appending progress only in top-level sessions, making it suitable for developers who need to maintain context across multiple sessions.