dsh-desktop-notify: Display Desktop Notifications When DeepSeek Harness Completes a Response

`dsh-desktop-notify` is a plugin that provides desktop notification functionality for DeepSeek Harness (DSH). It uses native system interfaces on Windows, macOS, and Linux to display a notification when an AI response is completed, including a summary of the response and session information. The plugin supports pushing notifications to multiple devices via HTTP APIs for cross-device reminders and allows custom icons. Installation requires specifying version 1.4.1 and restarting the process. All data is stored locally and does not depend on any external account system.