dsh-plugin-template: DeepSeek Harness Plugin Skeleton

`dsh-plugin-template` is a DeepSeek Harness plugin development skeleton maintained by `sunshine-lang` (MIT license), designed to simplify the plugin creation process. This template centralizes core components such as bundle formats, tool DSL, configuration validation, testing, and release checks. Developers can quickly generate a plugin directory using the `scaffold` script, then supplement tool logic and configurations as needed, and finalize documentation following the release checklist. The template supports two build paths: using `pnpm` with `tsconfig.local.json` within the harness repository, or cloning independently and building with `npm`. During development, specific conventions must be followed, such as omitting the `required` field for optional parameters.