fix(google): classify embedding models by supportedGenerationMethods (#14)

* fix(google): classify embedding models by supportedGenerationMethods

ListModels was hardcoding all Google models as sdk.ModelTypeChat,
discarding the supportedGenerationMethods field already parsed in
googleModelObject. Models with only "embedContent" (no "generateContent")
are now correctly classified as sdk.ModelTypeEmbedding.

Also adds ModelTypeEmbedding constant to the sdk package.

Ref: memohai/Memoh#533

* docs: add ModelTypeEmbedding to API reference and skill docs

Author: qqqqqf-q

docs/api-reference.md

@@ -111,7 +111,8 @@ type Model struct {
 }
 
 type ModelType string
-const ModelTypeChat ModelType = "chat"
+const ModelTypeChat      ModelType = "chat"
+const ModelTypeEmbedding ModelType = "embedding"
 ```
 
 #### Methods

provider/google/generativeai/generativeai.go

@@ -74,7 +74,7 @@ func (p *Provider) ListModels(ctx context.Context) ([]sdk.Model, error) {
 			ID:          id,
 			DisplayName: m.DisplayName,
 			Provider:    p,
-			Type:        sdk.ModelTypeChat,
+			Type:        googleModelType(m.SupportedGenerationMethods),
 		})
 	}
 	return models, nil
@@ -134,6 +134,23 @@ func (p *Provider) ChatModel(id string) *sdk.Model {
 	}
 }
 
+func googleModelType(methods []string) sdk.ModelType {
+	hasGenerate := false
+	hasEmbed := false
+	for _, m := range methods {
+		switch m {
+		case "generateContent":
+			hasGenerate = true
+		case "embedContent":
+			hasEmbed = true
+		}
+	}
+	if hasEmbed && !hasGenerate {
+		return sdk.ModelTypeEmbedding
+	}
+	return sdk.ModelTypeChat
+}
+
 // ---------- DoGenerate ----------
 
 func (p *Provider) DoGenerate(ctx context.Context, params sdk.GenerateParams) (*sdk.GenerateResult, error) { //nolint:gocritic // interface method

provider/google/generativeai/generativeai_test.go

@@ -1106,6 +1106,49 @@ func TestListModels(t *testing.T) {
 	if models[0].DisplayName != "Gemini 2.5 Pro" {
 		t.Errorf("expected display name 'Gemini 2.5 Pro', got %q", models[0].DisplayName)
 	}
+	if models[0].Type != sdk.ModelTypeChat {
+		t.Errorf("expected chat type for model without supportedGenerationMethods, got %q", models[0].Type)
+	}
+}
+
+func TestListModels_EmbeddingType(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]any{
+			"models": []map[string]any{
+				{
+					"name":                       "models/gemini-2.5-flash",
+					"displayName":                "Gemini 2.5 Flash",
+					"supportedGenerationMethods": []string{"generateContent", "countTokens"},
+				},
+				{
+					"name":                       "models/gemini-embedding-001",
+					"displayName":                "Gemini Embedding 001",
+					"supportedGenerationMethods": []string{"embedContent", "countTokens"},
+				},
+			},
+		})
+	}))
+	defer srv.Close()
+
+	p := generativeai.New(
+		generativeai.WithAPIKey("test-key"),
+		generativeai.WithBaseURL(srv.URL),
+	)
+
+	models, err := p.ListModels(context.Background())
+	if err != nil {
+		t.Fatalf("ListModels failed: %v", err)
+	}
+	if len(models) != 2 {
+		t.Fatalf("expected 2 models, got %d", len(models))
+	}
+	if models[0].Type != sdk.ModelTypeChat {
+		t.Errorf("expected chat type for generateContent model, got %q", models[0].Type)
+	}
+	if models[1].Type != sdk.ModelTypeEmbedding {
+		t.Errorf("expected embedding type for embedContent model, got %q", models[1].Type)
+	}
 }
 
 func TestProviderTest_OK(t *testing.T) {

sdk/model.go

@@ -5,7 +5,8 @@ import "context"
 type ModelType string
 
 const (
-	ModelTypeChat ModelType = "chat"
+	ModelTypeChat      ModelType = "chat"
+	ModelTypeEmbedding ModelType = "embedding"
 )
 
 type Model struct {

skill/reference.md

@@ -79,7 +79,8 @@ type ModelTestResult struct {
 ```go
 type ModelType string
 
-const ModelTypeChat ModelType = "chat"
+const ModelTypeChat      ModelType = "chat"
+const ModelTypeEmbedding ModelType = "embedding"
 
 type Model struct {
     ID          string