fix: 转发失败日志添加账户ID信息

backend/internal/handler/gateway_handler.go

@@ -373,7 +373,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 				continue
 			}
 			// 错误响应已在Forward中处理，这里只记录日志
-			log.Printf("Forward request failed: %v", err)
+			log.Printf("Account %d: Forward request failed: %v", account.ID, err)
 			return
 		}
 

backend/internal/handler/openai_gateway_handler.go

@@ -225,7 +225,7 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 				continue
 			}
 			// Error response already handled in Forward, just log
-			log.Printf("Forward request failed: %v", err)
+			log.Printf("Account %d: Forward request failed: %v", account.ID, err)
 			return
 		}