dsh-pwsh-direct: DSH Desktop Built-in pwsh/shell Empty Results Fix and Fallback Tool

The DSH Desktop plugin `dsh-pwsh-direct` is used to fix a bug where the built-in PowerShell and Shell return empty results. It repairs sandboxed environment variables through a self-healing mechanism and provides the `pwsh_direct` tool as a fallback. The plugin modifies the DSH installation directory, requires administrator privileges, and supports only Windows and Node.js 20 or later. DSH Desktop must be restarted after installation.