feat(distribution): 优化一键同步主站商品功能（并发防重、分批入库、失效商品联动下架与初始加价）

- 后端优化：
  - 引入 Redis + 内存 sync.Map 双重互斥锁，避免并发/连击导致唯一索引冲突 (ErrSyncInProgress)
  - 使用 CreateInBatches(500) 进行大数据量批量插入，杜绝超长 SQL 与锁表超时
  - 增加 CleanStaleListings 支持，自动排查并联动下架主站非在售的货架商品，清理历史幽灵数据
  - 增加 DefaultShelfRatioDelta 支持，新同步商品直接继承初始加价比例，免除二次手动改价
- 前端优化：
  - distribution-admin 货架管理新增一键同步配置弹窗（可勾选自动下架失效商品、配置初始加价）
  - 同步完成后展示结构化统计弹窗（新增、保持、联动下架、主站在售总量）
  - 前后端类型定义与 API 客户端对齐升级
- 测试覆盖：
  - 补充 TestSyncSiteAccountsOptimizations 单元测试与 handler 集成测试
  - 全工程测试与门禁 check.sh 100% 通过

backend/internal/modules/distribution/repository.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"slices"
 	"strings"
+	"sync"
 	"time"
 
 	"hfb_sys/backend/internal/auditlog"
@@ -64,8 +65,9 @@ func normalizeSettlementHoldDays(days int) (int, error) {
 }
 
 type Repository struct {
-	db    *gorm.DB
-	redis *redis.Client
+	db            *gorm.DB
+	redis         *redis.Client
+	siteSyncLocks sync.Map
 }
 
 func NewRepository(db *gorm.DB, redis ...*redis.Client) *Repository {
@@ -914,7 +916,7 @@ func uniquePositiveIDs(ids []uint64) []uint64 {
 	return out
 }
 
-func (r *Repository) SyncSiteAccounts(ctx context.Context, adminID, siteID uint64, listingIDs []uint64) (*SyncSiteAccountsResult, error) {
+func (r *Repository) SyncSiteAccounts(ctx context.Context, adminID, siteID uint64, req SyncSiteAccountsRequest) (*SyncSiteAccountsResult, error) {
 	if r.db == nil {
 		return nil, ErrDependencyUnavailable
 	}
@@ -929,7 +931,30 @@ func (r *Repository) SyncSiteAccounts(ctx context.Context, adminID, siteID uint6
 		return nil, err
 	}
 
-	selectedIDs := uniquePositiveIDs(listingIDs)
+	if req.DefaultShelfRatioDelta < 0 {
+		return nil, ErrInvalidAmount
+	}
+
+	// 1. 防重复并发锁（Redis 分布式锁 + 内存 sync.Map 双重互斥保障）
+	lockKey := fmt.Sprintf("dist:sync_accounts:%d", siteID)
+	if r.redis != nil {
+		ok, err := r.redis.SetNX(ctx, lockKey, 1, 30*time.Second).Result()
+		if err == nil {
+			if !ok {
+				return nil, ErrSyncInProgress
+			}
+			defer func() {
+				_ = r.redis.Del(context.Background(), lockKey).Err()
+			}()
+		}
+	}
+	_, loaded := r.siteSyncLocks.LoadOrStore(siteID, struct{}{})
+	if loaded {
+		return nil, ErrSyncInProgress
+	}
+	defer r.siteSyncLocks.Delete(siteID)
+
+	selectedIDs := uniquePositiveIDs(req.ListingIDs)
 	if len(selectedIDs) > maxSyncListingIDs {
 		return nil, ErrTooManySyncListings
 	}
@@ -969,6 +994,7 @@ func (r *Repository) SyncSiteAccounts(ctx context.Context, adminID, siteID uint6
 	var toInsert []model.DistributionSiteAccount
 	seenAccount := make(map[uint64]bool)
 	var skippedCount int64
+	var updatedCount int64
 
 	for _, l := range candidates {
 		if seenAccount[l.AccountID] {
@@ -980,28 +1006,55 @@ func (r *Repository) SyncSiteAccounts(ctx context.Context, adminID, siteID uint6
 			if ea.ListingID != l.ID {
 				_ = r.db.WithContext(ctx).Model(&model.DistributionSiteAccount{}).
 					Where("id = ?", ea.ID).Update("listing_id", l.ID).Error
+				updatedCount++
 			}
 			skippedCount++
 		} else {
 			toInsert = append(toInsert, model.DistributionSiteAccount{
-				SiteID:        siteID,
-				AccountID:     l.AccountID,
-				ListingID:     l.ID,
-				DisplayStatus: "enabled",
+				SiteID:          siteID,
+				AccountID:       l.AccountID,
+				ListingID:       l.ID,
+				DisplayStatus:   "enabled",
+				ShelfRatioDelta: req.DefaultShelfRatioDelta,
 			})
 		}
 	}
 
+	// 2. 分批高效入库，防止大数据量超长 SQL 或锁表超时
 	if len(toInsert) > 0 {
-		if err := r.db.WithContext(ctx).Create(&toInsert).Error; err != nil {
+		if err := r.db.WithContext(ctx).CreateInBatches(&toInsert, 500).Error; err != nil {
 			return nil, err
 		}
 	}
 
+	// 3. 联动下架主站非在售/已失效的货架商品（若开启 CleanStaleListings）
+	var disabledStaleCount int64
+	if req.CleanStaleListings {
+		var staleIDs []uint64
+		err := r.db.WithContext(ctx).Table("distribution_site_accounts AS dsa").
+			Joins("LEFT JOIN rental_listings AS l ON l.id = dsa.listing_id AND l.status = 'published' AND l.review_status = 'approved'").
+			Where("dsa.site_id = ? AND dsa.display_status = 'enabled' AND l.id IS NULL", siteID).
+			Pluck("dsa.id", &staleIDs).Error
+		if err == nil && len(staleIDs) > 0 {
+			for i := 0; i < len(staleIDs); i += 500 {
+				end := i + 500
+				if end > len(staleIDs) {
+					end = len(staleIDs)
+				}
+				_ = r.db.WithContext(ctx).Model(&model.DistributionSiteAccount{}).
+					Where("id IN ?", staleIDs[i:end]).
+					Update("display_status", "disabled").Error
+			}
+			disabledStaleCount = int64(len(staleIDs))
+		}
+	}
+
 	return &SyncSiteAccountsResult{
-		SyncedCount:  int64(len(toInsert)),
-		SkippedCount: skippedCount,
-		TotalActive:  int64(len(candidates)),
+		SyncedCount:        int64(len(toInsert)),
+		SkippedCount:       skippedCount,
+		UpdatedCount:       updatedCount,
+		DisabledStaleCount: disabledStaleCount,
+		TotalActive:        int64(len(candidates)),
 	}, nil
 }