guanzi279-source/dsh-peak-valley-countdown: DeepSeek peak-valley billing switch countdown below the input box

This article introduces the community plugin `guanzi279-source/dsh-peak-valley-countdown`. It registers in the `conversation.composer.dock` slot to display a countdown for the switch between DeepSeek API peak and off-peak hours below the input box. The countdown is calculated strictly based on Beijing Time (UTC+8), automatically displaying the number of days when crossing weekends and statutory holidays, and includes a built-in table of 2026 Chinese statutory holidays. The plugin does not connect to the internet, write files, or report data; it only reads the system clock. The article provides installation commands via npm and GitHub, typical usage examples, and notes on compatibility, permissions, and licensing.