dsh-plugin-development: Auxiliary Skills for DSH Plugin Development

The DSH plugin development assistant `dsh-plugin-development` is an open-source tool designed to help with developing, debugging, and publishing DSH plugins. Its core features include providing dual half-package scaffolding, supporting development against a fork and three-level validation, supporting publishing and remote deployment, and including a troubleshooting checklist for common pitfalls. After installation, the plugin registers the `skills/` directory in the package as the skill root. It works by leveraging the `cordis.patch.yml` extension mechanism and depends on `@deepseek-ai/dsh-skill-filesystem`. Developers should note that the plugin runs with the permissions of the current DSH process, and it provides a specific solution for scenarios in which the host plugin runs in a PowerShell subprocess.