dsh-wsl-ssh-agent: SSH Agent Diagnostics and Forwarding Tips in WSL

`dsh-wsl-ssh-agent` is a diagnostic plugin in the DeepSeek Harness (DSH) suite, designed to address configuration troubleshooting challenges in WSL when reusing the Windows OpenSSH agent caused by path, permission, or connection-state issues. The tool focuses on checking whether the SSH agent socket exists and whether the `npiperelay` bridge is functioning properly, while never printing key material to ensure security. By using the `ssh_agent_hint` tool, users can quickly verify that the forwarding path is working correctly, providing a standardized solution for SSH agent debugging under WSL in DeepSeek Harness.