dsh-plugin-model-provider: Append the platform to the model name

In the DSH chat interface, the model selector displays only the model name, making it difficult to distinguish which platform a similarly named model originates from when connecting to multiple platforms. The `dsh-plugin-model-provider` appends the platform name to the model name in the 'Model' row of the modal and the model button above the input box, while keeping the dropdown candidate list unchanged. Starting from version 0.0.2, it uses pure DOM decoration without registering slots. It wraps the `Response` from the private `/api/session/modelCatalog` endpoint to learn the mapping and renders the platform name using CSS `::after`. Compatible with DSH >= 0.2.1-rc.3, React ^18.2.0, and Web only, it is licensed under MIT and provides two installation methods (manual dependency via file and `dsh plugin add`) along with fallback steps.