dsh-sidebar-ratio: Proportional Sidebar Adjustment and Panel Inheritance

The DSH plugin `dsh-sidebar-ratio` is designed to address the issues of a fixed sidebar width and lost panel state when switching panels in the web version of DeepSeek Harness. By taking over styles and using the official API, it supports adjusting the sidebar width according to the window ratio and sharing the right-side panel across sessions within the same parent session group. The plugin provides shortcuts and console APIs for configuration and control, requires a restart to take effect, and does not modify the source code.