feat(adtracking): 新增推广链接追踪与数据大盘，支持自定义短码、注册与下单归因及二维码物料生成

1. 数据库新增 000064_ad_tracking.sql 迁移，创建 ad_tracking_links 和 ad_tracking_clicks 表，并在 users、rental_orders 增加归因字段
2. 后端新增 adtracking 模块，挂载 GET /r/:code 302 智能重定向、点击流水异步记录、转化率/GMV聚合统计及管理接口
3. 用户认证 (auth) 与订单创建 (order) 链路贯通，实现注册用户与订单成交推广短码全链路归因
4. 前端管理后台左侧新增【推广追踪】目录，支持大盘指标总览、推广链接 CRUD、状态启停、一键复制短链及二维码下载 (PNG)

backend/internal/modules/order/dto.go

@@ -75,6 +75,7 @@ type OrderDTO struct {
 	Checkout                    *CheckoutDTO      `json:"checkout,omitempty"`
 	AdminActions                *AdminActionsDTO  `json:"admin_actions,omitempty"`
 	PaymentDeadlineAt           *time.Time        `json:"payment_deadline_at,omitempty"`
+	SourceTrackCode             string            `json:"source_track_code,omitempty"`
 	CreatedAt                   time.Time         `json:"created_at"`
 	UpdatedAt                   time.Time         `json:"updated_at"`
 }
@@ -105,6 +106,7 @@ type ActiveDisputeDTO struct {
 
 type CreateRequest struct {
 	ListingID uint64 `json:"listing_id" binding:"required"`
+	TrackCode string `json:"track_code,omitempty"`
 }
 
 type SubmitHandoffRequest struct {

backend/internal/modules/order/lifecycle.go

@@ -3,6 +3,7 @@ package order
 import (
 	"context"
 	"encoding/json"
+	"strings"
 	"time"
 
 	"hfb_sys/backend/internal/model"
@@ -70,6 +71,13 @@ func (r *Repository) Create(ctx context.Context, renterID uint64, req CreateRequ
 		if err != nil {
 			return err
 		}
+		sourceTrackCode := strings.TrimSpace(req.TrackCode)
+		if sourceTrackCode == "" {
+			var u model.User
+			if err := tx.Select("register_track_code").First(&u, renterID).Error; err == nil && u.RegisterTrackCode != "" {
+				sourceTrackCode = u.RegisterTrackCode
+			}
+		}
 		order := model.RentalOrder{
 			OrderNo:                     orderNo,
 			ListingID:                   listing.ID,
@@ -103,6 +111,7 @@ func (r *Repository) Create(ctx context.Context, renterID uint64, req CreateRequ
 			ManagedAdminID:              listing.ManagedAdminID,
 			SettlementStatus:            settlementStatusUnsettled,
 			OfflineSettlementStatus:     offlineSettlementStatusNone,
+			SourceTrackCode:             sourceTrackCode,
 		}
 		if err := tx.Create(&order).Error; err != nil {
 			return err

backend/internal/modules/order/presenter.go

@@ -128,6 +128,7 @@ func (row orderRow) toAdminDTO() OrderDTO {
 		DepositHeldAt:               row.DepositHeldAt,
 		DepositHoldReleasedAt:       row.DepositHoldReleasedAt,
 		AdminActions:                adminActionsForOrder(row.RentalOrder),
+		SourceTrackCode:             row.SourceTrackCode,
 		CreatedAt:                   row.CreatedAt,
 		UpdatedAt:                   row.UpdatedAt,
 	}