dsh-theme-picker: DeepSeek Harness Theme Selection Plugin

dsh-theme-picker is a theme management plugin for DeepSeek Harness, designed to address the fragmentation and inconvenience of managing third-party theme plugins. It provides a unified Theme settings page that supports switching between the app's base theme and installed skin plugins. Its core features include unified management of app and plugin themes, an exclusive single-theme mode (enabling one plugin automatically disables others), real-time status synchronization (refreshed every 6 seconds), and Chinese/English interface switching. Installation requires the host kernel to meet the version requirement, and the plugin can be enabled in the settings panel after a restart. It is open-sourced under the MIT License, integrates with the market by calling the dsh-market API, and ensures that only one theme is active at a time.