dsh-shell-wsl: A Real Linux Bash Execution Environment for DSH on Windows

The `dsh-shell-wsl` plugin addresses the poor isolation and state-persistence issues of native Bash tools on Windows. By running Bash in disposable Docker containers, it provides a genuine Linux environment with integrated permission presets. The plugin does not require the model to be aware of new tools, remains compatible with the official Bash interface, and automatically destroys containers to maintain a clean environment. Installation requires Docker Desktop and a WSL2 distro, making it suitable for high-isolation Linux development scenarios.