Rename the admin-managed SDK resource from `ChatModelConfig` to
`ChatModel`. Rename catalog entries from `ChatModel` to
`ChatModelCatalogEntry` and replace `ChatModelsResponse` with
`ChatModelAvailabilityResponse`.
API routes and JSON fields do not change. Experimental SDK and OpenAPI
schema names do change.
Depends on #27957
_This pull request description was generated by Coder Agents._
Ethan
9bd8899359