dsh-notify-windows: Adding Windows Desktop Notifications to DSH

dsh-notify-windows is a DeepSeek Harness (DSH) plugin maintained by SeverusZh, designed specifically for Windows 10/11. It aims to address the issue where users cannot promptly learn about the status of DSH tasks when they are away from the screen, enabling unobtrusive monitoring by sending Windows system desktop notifications at key milestones. Core features include: listening for session `turn/end` events to alert users when tasks complete, encounter errors, or exceed output limits; listening for `approval/asked` events to alert users when manual approval is required (automatically skipped under the `never` policy); and recognizing Agent questions (e.g., `ask_user_question`) to prompt users for responses. The plugin ignores sub-agent sessions by default, with configuration options available to enable them.