fix: 删除未使用的代码并修复格式

- 删除 client.go 中未使用的 proxyURL 字段
- 删除 AntigravityGatewayService 中未使用的字段和方法
- 修复 gofmt 格式问题

backend/internal/pkg/antigravity/client.go

@@ -74,7 +74,6 @@ func (r *LoadCodeAssistResponse) GetTier() string {
 // Client Antigravity API 客户端
 type Client struct {
 	httpClient *http.Client
-	proxyURL   string
 }
 
 func NewClient(proxyURL string) *Client {
@@ -92,7 +91,6 @@ func NewClient(proxyURL string) *Client {
 
 	return &Client{
 		httpClient: client,
-		proxyURL:   proxyURL,
 	}
 }
 

backend/internal/service/antigravity_gateway_service.go

@@ -55,23 +55,19 @@ var antigravityModelMapping = map[string]string{
 
 // AntigravityGatewayService 处理 Antigravity 平台的 API 转发
 type AntigravityGatewayService struct {
-	accountRepo      AccountRepository
-	cache            GatewayCache
 	tokenProvider    *AntigravityTokenProvider
 	rateLimitService *RateLimitService
 	httpUpstream     HTTPUpstream
 }
 
 func NewAntigravityGatewayService(
-	accountRepo AccountRepository,
-	cache GatewayCache,
+	_ AccountRepository,
+	_ GatewayCache,
 	tokenProvider *AntigravityTokenProvider,
 	rateLimitService *RateLimitService,
 	httpUpstream HTTPUpstream,
 ) *AntigravityGatewayService {
 	return &AntigravityGatewayService{
-		accountRepo:      accountRepo,
-		cache:            cache,
 		tokenProvider:    tokenProvider,
 		rateLimitService: rateLimitService,
 		httpUpstream:     httpUpstream,
@@ -163,33 +159,6 @@ func (s *AntigravityGatewayService) unwrapV1InternalResponse(body []byte) ([]byt
 	return body, nil
 }
 
-// unwrapSSELine 解包 SSE 行中的 v1internal 响应
-func (s *AntigravityGatewayService) unwrapSSELine(line string) string {
-	if !strings.HasPrefix(line, "data: ") {
-		return line
-	}
-
-	data := strings.TrimPrefix(line, "data: ")
-	if data == "" || data == "[DONE]" {
-		return line
-	}
-
-	var outer map[string]any
-	if err := json.Unmarshal([]byte(data), &outer); err != nil {
-		return line
-	}
-
-	if resp, ok := outer["response"]; ok {
-		unwrapped, err := json.Marshal(resp)
-		if err != nil {
-			return line
-		}
-		return "data: " + string(unwrapped)
-	}
-
-	return line
-}
-
 // Forward 转发 Claude 协议请求（Claude → Gemini 转换）
 func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context, account *Account, body []byte) (*ForwardResult, error) {
 	startTime := time.Now()
@@ -568,81 +537,6 @@ type antigravityStreamResult struct {
 	firstTokenMs *int
 }
 
-func (s *AntigravityGatewayService) handleStreamingResponse(c *gin.Context, resp *http.Response, startTime time.Time, originalModel string) (*antigravityStreamResult, error) {
-	c.Header("Content-Type", "text/event-stream")
-	c.Header("Cache-Control", "no-cache")
-	c.Header("Connection", "keep-alive")
-	c.Header("X-Accel-Buffering", "no")
-	c.Status(http.StatusOK)
-
-	flusher, ok := c.Writer.(http.Flusher)
-	if !ok {
-		return nil, errors.New("streaming not supported")
-	}
-
-	usage := &ClaudeUsage{}
-	var firstTokenMs *int
-	reader := bufio.NewReader(resp.Body)
-
-	for {
-		line, err := reader.ReadString('\n')
-		if err != nil && !errors.Is(err, io.EOF) {
-			return nil, fmt.Errorf("stream read error: %w", err)
-		}
-
-		if len(line) > 0 {
-			// 解包 v1internal 响应
-			unwrapped := s.unwrapSSELine(strings.TrimRight(line, "\r\n"))
-
-			// 解析 usage
-			if strings.HasPrefix(unwrapped, "data: ") {
-				data := strings.TrimPrefix(unwrapped, "data: ")
-				if data != "" && data != "[DONE]" {
-					if firstTokenMs == nil {
-						ms := int(time.Since(startTime).Milliseconds())
-						firstTokenMs = &ms
-					}
-					s.parseClaudeSSEUsage(data, usage)
-				}
-			}
-
-			// 写入响应
-			if _, writeErr := fmt.Fprintf(c.Writer, "%s\n", unwrapped); writeErr != nil {
-				return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, writeErr
-			}
-			flusher.Flush()
-		}
-
-		if errors.Is(err, io.EOF) {
-			break
-		}
-	}
-
-	return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, nil
-}
-
-func (s *AntigravityGatewayService) handleNonStreamingResponse(c *gin.Context, resp *http.Response, originalModel string) (*ClaudeUsage, error) {
-	body, err := io.ReadAll(io.LimitReader(resp.Body, 8<<20))
-	if err != nil {
-		return nil, s.writeClaudeError(c, http.StatusBadGateway, "upstream_error", "Failed to read upstream response")
-	}
-
-	// 解包 v1internal 响应
-	unwrapped, err := s.unwrapV1InternalResponse(body)
-	if err != nil {
-		return nil, s.writeClaudeError(c, http.StatusBadGateway, "upstream_error", "Failed to parse upstream response")
-	}
-
-	// 解析 usage
-	var respObj struct {
-		Usage ClaudeUsage `json:"usage"`
-	}
-	_ = json.Unmarshal(unwrapped, &respObj)
-
-	c.Data(http.StatusOK, "application/json", unwrapped)
-	return &respObj.Usage, nil
-}
-
 func (s *AntigravityGatewayService) handleGeminiStreamingResponse(c *gin.Context, resp *http.Response, startTime time.Time) (*antigravityStreamResult, error) {
 	c.Status(resp.StatusCode)
 	c.Header("Cache-Control", "no-cache")
@@ -734,44 +628,6 @@ func (s *AntigravityGatewayService) handleGeminiNonStreamingResponse(c *gin.Cont
 	return &ClaudeUsage{}, nil
 }
 
-func (s *AntigravityGatewayService) parseClaudeSSEUsage(data string, usage *ClaudeUsage) {
-	// 解析 message_start 获取 input tokens
-	var msgStart struct {
-		Type    string `json:"type"`
-		Message struct {
-			Usage ClaudeUsage `json:"usage"`
-		} `json:"message"`
-	}
-	if json.Unmarshal([]byte(data), &msgStart) == nil && msgStart.Type == "message_start" {
-		usage.InputTokens = msgStart.Message.Usage.InputTokens
-		usage.CacheCreationInputTokens = msgStart.Message.Usage.CacheCreationInputTokens
-		usage.CacheReadInputTokens = msgStart.Message.Usage.CacheReadInputTokens
-	}
-
-	// 解析 message_delta 获取 output tokens
-	var msgDelta struct {
-		Type  string `json:"type"`
-		Usage struct {
-			InputTokens              int `json:"input_tokens"`
-			OutputTokens             int `json:"output_tokens"`
-			CacheCreationInputTokens int `json:"cache_creation_input_tokens"`
-			CacheReadInputTokens     int `json:"cache_read_input_tokens"`
-		} `json:"usage"`
-	}
-	if json.Unmarshal([]byte(data), &msgDelta) == nil && msgDelta.Type == "message_delta" {
-		usage.OutputTokens = msgDelta.Usage.OutputTokens
-		if usage.InputTokens == 0 {
-			usage.InputTokens = msgDelta.Usage.InputTokens
-		}
-		if usage.CacheCreationInputTokens == 0 {
-			usage.CacheCreationInputTokens = msgDelta.Usage.CacheCreationInputTokens
-		}
-		if usage.CacheReadInputTokens == 0 {
-			usage.CacheReadInputTokens = msgDelta.Usage.CacheReadInputTokens
-		}
-	}
-}
-
 func (s *AntigravityGatewayService) writeClaudeError(c *gin.Context, status int, errType, message string) error {
 	c.JSON(status, gin.H{
 		"type":  "error",