Revert "feat(gateway): 实现负载感知的账号调度优化 (#114)"

This reverts commit 8d252303fc.

backend/internal/service/antigravity_gateway_service.go

@@ -358,15 +358,6 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 		return nil, fmt.Errorf("transform request: %w", err)
 	}
 
-	// 调试：记录转换后的请求体（仅记录前 2000 字符）
-	if bodyJSON, err := json.Marshal(geminiBody); err == nil {
-		truncated := string(bodyJSON)
-		if len(truncated) > 2000 {
-			truncated = truncated[:2000] + "..."
-		}
-		log.Printf("[Debug] Transformed Gemini request: %s", truncated)
-	}
-
 	// 构建上游 action
 	action := "generateContent"
 	if claudeReq.Stream {