dsh-setting-manager: Show/Hide Control for Settings Page Section Navigation

The dsh-setting-manager plugin provides batch show/hide control for DeepSeek Harness setting sections through the right-click menu. It uses `display:none` to hide sections, persists their state to a local JSON file, and supports reuse across browser sessions. It strictly follows the DSH theme, incorporates security validation mechanisms (such as loopback restrictions and protection against DNS attacks), and offers batch operations with fault-tolerant fallback. The plugin is easy to install and aims to resolve the cumbersome navigation caused by an excessive number of sections.