dsh-pwsh-rtk-rewrite: A Native rtk Command Bridging Plugin for DeepSeek Harness

`dsh-pwsh-rtk-rewrite` is a native rtk bridge plugin for DeepSeek Harness (DSH), designed to use the rtk rewrite mechanism to convert native shell commands into compact rtk commands and save tokens. It supports Windows + PowerShell and provides transparent rewriting, preservation of sandbox semantics, and automatic fallback on failure. By automatically segmenting and rewriting composite commands (e.g., `git status` -> `rtk git status`), it addresses verbose native shell output while keeping the tool-call logic unchanged.