dsh-awake: DeepSeek Harness Keep-Awake Plugin

`dsh-awake` is a DeepSeek Harness plugin that prevents the operating system from entering sleep mode during task execution to avoid task interruption or data corruption, automatically restoring the original state after the task completes. It supports Windows, Linux, and macOS. Dynamic configuration enables hot updates, and sleep prevention is implemented using system-native mechanisms such as `systemd-inhibit` and `caffeinate`. Configuration options include watchdog mode, platform adaptation, and an always-on switch. The plugin supports one-click updates and automatic migration, is built with TypeScript, and uses a single API channel for data-plane transmission.