dsh-subprocess-win32: Native Windows Subprocess Runtime and Presets for DeepSeek Harness

`dsh-subprocess-win32` is a Cordis runtime plugin designed for DeepSeek Harness (DSH), aimed at resolving process leakage issues caused by Unix-style subprocesses in Windows environments. The plugin provides a native Windows subprocess engine, optimized lightweight and standard Agent presets, and a secure PowerShell lifecycle manager. Users can diagnose, install, update, and uninstall it via the `$setup` script. After installation, the corresponding Windows preset must be selected in DSH to enable the feature. Note that Git/MSYS Bash may report errors when restricted writes occur, and uninstallation removes only DSH components without affecting project source code.