dsh-laa: DeepSeek Peak and Off-Peak Billing Optimization Plugin

`dsh-laa` is a peak/off-peak hour optimization plugin for DeepSeek's official pricing. It leverages DeepSeek's peak/off-peak billing mechanism, automatically pausing sessions during peak hours to reduce costs and resuming them during off-peak hours. The plugin provides session-level control, a Web UI, and API interfaces, supporting both automatic switching and manual adjustment. It applies only to the `deepseek-official` provider, with child sessions following the parent session. The configuration file is located at `cordis.patch.yml`, where users can customize the time zone, peak-hour windows, and notification policies.