dsh-plugin-task-coordinator: Cross-Task Orchestration Plugin for DeepSeek Harness

`dsh-plugin-task-coordinator` is a plugin for DeepSeek Harness (DSH) designed to address the challenges of agents managing multiple parallel subtasks. It provides a `task_*` toolset supporting core functions such as task scheduling, monitoring, parallel dispatch, result collection, and interactive confirmation, and it can control workspaces and models. Installation requires a specific Node.js version and PowerShell environment, and the installation script automatically backs up and registers the plugin. When using it, instructions should be explicit and phrased in the imperative mood to ensure the model invokes the tools correctly. The plugin enables supervisor sessions to perform complex cross-task coordination through a standard interface.