DeepSeek Harness Cost Statistics Plugin

`dsh-cost-tracker` is a cost monitoring plugin developed for DeepSeek Harness. It listens to model invocation events, calculates costs in real time based on token usage and pricing schedules, supports peak and off-peak pricing strategies, and persistently stores records. Core features include monitoring and converting token usage into costs, local data persistence, and providing a three-tier UI statistics dashboard (per-invocation details, session-level summaries, and a global statistics page). Users can install it via npm and configure it in `cordis.yml` or a web profile. The plugin is compatible with DSH 0.1.5-rc.1, can run independently in node mode, and aims to provide developers with lightweight cost monitoring capabilities.