dsh-bgjobs: Submit DSH Tasks for Independent Background Execution

The `dsh-bgjobs` plugin leverages Windows Task Scheduler to resolve interruptions in long-running DSH tasks. It enables tasks to run independently of the DSH process and supports real-time monitoring, post-disconnection tracking, and completion notifications. The plugin provides tools such as `bgjob_submit` and `bgjob_wait`, and supports PowerShell, MCP calls, and sandbox mode. Prerequisites are Windows, PowerShell 7, and Node.js.