feat: support VertexAI provider (#153)

* support: vertexai

fix

fix

set default for vertexai

added comment

fix

fix

* create schema

* fix README.md

* fix order

* added pupularity

* set tools if tools is exists

restore commentout

* fix comment

* set summarizer model

internal/llm/provider/provider.go

@@ -123,6 +123,11 @@ func NewProvider(providerName models.ModelProvider, opts ...ProviderClientOption
 			options: clientOptions,
 			client:  newAzureClient(clientOptions),
 		}, nil
+	case models.ProviderVertexAI:
+		return &baseProvider[VertexAIClient]{
+			options: clientOptions,
+			client:  newVertexAIClient(clientOptions),
+		}, nil
 	case models.ProviderOpenRouter:
 		clientOptions.openaiOptions = append(clientOptions.openaiOptions,
 			WithOpenAIBaseURL("https://openrouter.ai/api/v1"),