dsh-sidebar-size: DeepSeek Harness Right Sidebar Size Persistence Plugin

The `dsh-sidebar-size` plugin aims to solve the issue in DeepSeek Harness of having to repeatedly adjust the right sidebar width when frequently switching tabs. It supports remembering sidebar sizes by tab type, features an inheritance mechanism and a unified width mode, and allows users to view status, export logs, and migrate data from Settings. Users can install it by downloading a `.tgz` file or from local source code. Developed for DSH Desktop v0.2.0-rc.x, the plugin does not modify host files; however, abnormal exits may result in data loss, and compatibility with the host application version must be maintained.