dsh-subagent-pi-plus: A True Gateway Subagent Plugin Based on Pi RPC

The DeepSeek Harness (DSH) plugin `dsh-subagent-pi-plus` integrates the local Pi command-line tool into DSH, enabling a “true gateway” direct connection. Through the Pi RPC protocol, the plugin allows DSH to act as a pass-through channel for communicating with local Pi sessions, supporting message queuing, real-time progress display, attachment pass-through, and coexistence with delegation mode. Users need to install the local `pi` tool and use the `/pi-lock` command to bind a session. When installing, note that the npm package name is `dsh-subagent-pi-plus`, not `dsh-subagent-pi`.