dsh-notify-win: Adding Windows native notifications to DeepSeek Harness

dsh-notify-win is a Windows native notification plugin for DeepSeek Harness (DSH) designed to solve the inefficiency of monitoring background task status. Developed by Andyqwe44 and licensed under the MIT License, the plugin uses a fire-and-forget mechanism to provide immediate alerts for DSH without requiring the registration of additional services or tools. Its core capabilities cover three key scenarios: task completion, context compression completion, and waiting for user input. Specific features include displaying native Toast notifications in the bottom right corner of Windows 10/11, triggering taskbar flashing via FlashWindowEx to alert background users, enabling direct focus and session switching upon clicking notifications, and providing native dropdown lists and custom options for single-choice questions.