feat: [STG-1756] forward Vertex model config

Author: stainless-app[bot]

.stats.yml

@@ -1,4 +1,4 @@
 configured_endpoints: 8
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/browserbase/stagehand-80502d74c1be605e77d45ff2b54297fe34ce85dbad1e8f2dfa30ba6d09601219.yml
-openapi_spec_hash: fd62f768756a400c3ecd695bfcf3845a
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/browserbase/stagehand-c7910965e66e73ad8b65b6cc391d431094b2a6c6577c3e9d82feaa8138e74cff.yml
+openapi_spec_hash: 37748bb69c22a9ce721d9b5a5861f964
 config_hash: 1fb12ae9b478488bc1e56bfbdc210b01

lib/stagehand/internal/type/union.rb

@@ -4,6 +4,17 @@ module Stagehand
   module Internal
     module Type
       # @api private
+      #
+      # @example
+      #   # `model_config` is a `Stagehand::ModelConfig`
+      #   case model_config
+      #   when Stagehand::ModelConfig::VertexModelConfigObject
+      #     puts(model_config.auth)
+      #   when Stagehand::ModelConfig::GenericModelConfigObject
+      #     puts(model_config.model_name)
+      #   else
+      #     puts(model_config)
+      #   end
       module Union
         include Stagehand::Internal::Type::Converter
         include Stagehand::Internal::Util::SorbetRuntimeSupport