dsh-skill-usage: DSH Sidebar Skill Center

The `dsh-skill-usage` plugin provides a sidebar Skill Center for the DeepSeek Harness web interface, addressing the lack of feedback in skill management. It supports real-time monitoring of skill usage, viewing history, and bulk-enabling skills, making them available for the entire conversation. Installation is simple and requires no configuration, making it ideal for users who need to quickly view and manage skills in bulk.