dsh-workspace-plugin: View Agent Traces in DSH Sessions and Manage Workspace Memory

# Introduction When running agent sessions with DeepSeek Harness (DSH), a common issue arises: the agent creates and modifies a large number of files during its operation and may submit state changes via tools, yet this information is not intuitive. To verify exactly which files the agent has touched, what artifacts have been produced, and which Memory proposals have been submitted, users often have to leave the chat interface to browse the file system. The dsh-workspace-plugin addresses this exact scenario. It adds a `Workspace` tab to the session view in the local DSH Web UI, enabling you to inspect the files touched by the agent, review session artifacts, and preview...