dsh-usage-widget: DSH Sidebar Usage Monitoring

dsh-usage-widget is a DeepSeek Harness plugin designed to address the pain point of frequently checking balances and interrupting the workflow. It provides a persistent compact widget at the bottom of the left sidebar, displaying DeepSeek account balance and Kimi Code quota (including the 5-hour window and weekly quota) in real time, with automatic refresh. The plugin supports two data-fetching paths: host routing mode and direct browser fallback. In host mode, the API key is configured via environment variables; in browser mode, users can store the key in the panel. The plugin requires no build and is ready to use after installation and restart, making it suitable for developers who need continuous monitoring of API usage.