dsh-side-monitor: A read-only monitoring plugin to view host status in real-time in the DSH sidebar

# Introduction When developing or operating with DeepSeek Harness (DSH), it is often necessary to know the current status of the host machine: CPU and memory usage, which processes are consuming resources, and whether containers are functioning correctly. The common practice is to open another terminal, connect to it, execute `top` and `docker ps`, and then switch back. `dsh-side-monitor` brings this functionality into the DSH interface: it provides a "System Monitor" entry in the left sidebar; clicking it opens a right-side panel displaying a real-time host overview, a process list, and Docker container status. The following sections introduce the positioning, functionality, and installation method of this plugin. # Plugin Positioning `dsh-side-monitor` is a system monitoring side plugin for DSH Web.