dsh-peak: Peak/Off-Peak Pricing Indicator for DeepSeek API

Starting August 16, 2026, DeepSeek API pricing changes to different rates for peak and off-peak periods. The dsh-peak plugin visually displays the current “PEAK” or “OFF-PEAK” status in the DeepSeek Harness interface and provides a countdown. It is installed via a command and includes a browser-side pill component (updated every 30 seconds) and a host-side `dsh_peak_status` tool. Users can query the status or plan tasks to avoid higher costs during peak periods. The plugin has no runtime dependencies and is released under the MIT License.