feat(sync): full code sync from release

backend/internal/pkg/antigravity/claude_types.go

@@ -152,6 +152,7 @@ var claudeModels = []modelDef{
 	{ID: "claude-sonnet-4-5", DisplayName: "Claude Sonnet 4.5", CreatedAt: "2025-09-29T00:00:00Z"},
 	{ID: "claude-sonnet-4-5-thinking", DisplayName: "Claude Sonnet 4.5 Thinking", CreatedAt: "2025-09-29T00:00:00Z"},
 	{ID: "claude-opus-4-6", DisplayName: "Claude Opus 4.6", CreatedAt: "2026-02-05T00:00:00Z"},
+	{ID: "claude-opus-4-6-thinking", DisplayName: "Claude Opus 4.6 Thinking", CreatedAt: "2026-02-05T00:00:00Z"},
 	{ID: "claude-sonnet-4-6", DisplayName: "Claude Sonnet 4.6", CreatedAt: "2026-02-17T00:00:00Z"},
 }
 
@@ -165,6 +166,8 @@ var geminiModels = []modelDef{
 	{ID: "gemini-3-pro-high", DisplayName: "Gemini 3 Pro High", CreatedAt: "2025-06-01T00:00:00Z"},
 	{ID: "gemini-3.1-pro-low", DisplayName: "Gemini 3.1 Pro Low", CreatedAt: "2026-02-19T00:00:00Z"},
 	{ID: "gemini-3.1-pro-high", DisplayName: "Gemini 3.1 Pro High", CreatedAt: "2026-02-19T00:00:00Z"},
+	{ID: "gemini-3.1-flash-image", DisplayName: "Gemini 3.1 Flash Image", CreatedAt: "2026-02-19T00:00:00Z"},
+	{ID: "gemini-3.1-flash-image-preview", DisplayName: "Gemini 3.1 Flash Image Preview", CreatedAt: "2026-02-19T00:00:00Z"},
 	{ID: "gemini-3-pro-preview", DisplayName: "Gemini 3 Pro Preview", CreatedAt: "2025-06-01T00:00:00Z"},
 	{ID: "gemini-3-pro-image", DisplayName: "Gemini 3 Pro Image", CreatedAt: "2025-06-01T00:00:00Z"},
 }

backend/internal/pkg/antigravity/claude_types_test.go

@@ -0,0 +1,26 @@
+package antigravity
+
+import "testing"
+
+func TestDefaultModels_ContainsNewAndLegacyImageModels(t *testing.T) {
+	t.Parallel()
+
+	models := DefaultModels()
+	byID := make(map[string]ClaudeModel, len(models))
+	for _, m := range models {
+		byID[m.ID] = m
+	}
+
+	requiredIDs := []string{
+		"claude-opus-4-6-thinking",
+		"gemini-3.1-flash-image",
+		"gemini-3.1-flash-image-preview",
+		"gemini-3-pro-image", // legacy compatibility
+	}
+
+	for _, id := range requiredIDs {
+		if _, ok := byID[id]; !ok {
+			t.Fatalf("expected model %q to be exposed in DefaultModels", id)
+		}
+	}
+}

backend/internal/pkg/antigravity/gemini_types.go

@@ -70,7 +70,7 @@ type GeminiGenerationConfig struct {
 	ImageConfig     *GeminiImageConfig    `json:"imageConfig,omitempty"`
 }
 
-// GeminiImageConfig Gemini 图片生成配置（仅 gemini-3-pro-image 支持）
+// GeminiImageConfig Gemini 图片生成配置（gemini-3-pro-image / gemini-3.1-flash-image 等图片模型支持）
 type GeminiImageConfig struct {
 	AspectRatio string `json:"aspectRatio,omitempty"` // "1:1", "16:9", "9:16", "4:3", "3:4"
 	ImageSize   string `json:"imageSize,omitempty"`   // "1K", "2K", "4K"

backend/internal/pkg/antigravity/oauth.go

@@ -53,7 +53,8 @@ const (
 var defaultUserAgentVersion = "1.19.6"
 
 // defaultClientSecret 可通过环境变量 ANTIGRAVITY_OAUTH_CLIENT_SECRET 配置
-var defaultClientSecret = "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"
+// 默认值使用占位符，生产环境请通过环境变量注入真实值。
+var defaultClientSecret = "GOCSPX-your-client-secret"
 
 func init() {
 	// 从环境变量读取版本号，未设置则使用默认值

backend/internal/pkg/antigravity/oauth_test.go

@@ -612,14 +612,14 @@ func TestBuildAuthorizationURL_参数验证(t *testing.T) {
 
 	expectedParams := map[string]string{
 		"client_id":              ClientID,
-		"redirect_uri":          RedirectURI,
-		"response_type":         "code",
-		"scope":                 Scopes,
-		"state":                 state,
-		"code_challenge":        codeChallenge,
-		"code_challenge_method": "S256",
-		"access_type":           "offline",
-		"prompt":                "consent",
+		"redirect_uri":           RedirectURI,
+		"response_type":          "code",
+		"scope":                  Scopes,
+		"state":                  state,
+		"code_challenge":         codeChallenge,
+		"code_challenge_method":  "S256",
+		"access_type":            "offline",
+		"prompt":                 "consent",
 		"include_granted_scopes": "true",
 	}
 
@@ -684,7 +684,7 @@ func TestConstants_值正确(t *testing.T) {
 	if err != nil {
 		t.Fatalf("getClientSecret 应返回默认值，但报错: %v", err)
 	}
-	if secret != "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" {
+	if secret != "GOCSPX-your-client-secret" {
 		t.Errorf("默认 client_secret 不匹配: got %s", secret)
 	}
 	if RedirectURI != "http://localhost:8085/callback" {