feat(pickup): 新增管理员线下提号功能

- 新建 admin_pickups 表独立于 rental_orders，不污染订单状态机与财务统计口径
- 提号中/已完成/已取消三态：创建锁定账号，完成时给卖家钱包加可用余额并下架 listing，取消解锁账号
- 完成时 listing 置 completed，复用现有 listingLockedForOwnerMutation 拦截再上架
- 管理端提号管理页（列表/创建/完成/取消/可提号账号搜索）+ 卖家端提号记录页
- 财务仪表盘新增线下提号独立统计块，与正常订单口径分离
- 钱包流水 label、状态标签、菜单入口同步补齐
- 优化卖家服务悬浮菜单为一行四个，尺寸与配色对齐买家服务

backend/internal/modules/pickup/service.go

@@ -0,0 +1,73 @@
+package pickup
+
+import (
+	"context"
+
+	"hfb_sys/backend/internal/auditlog"
+)
+
+type Service struct {
+	repo *Repository
+}
+
+func NewService(repo *Repository) *Service {
+	return &Service{repo: repo}
+}
+
+func (s *Service) Create(ctx context.Context, req CreateRequest, adminID uint64, meta auditlog.Meta) (*PickupDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	if req.ListingID == 0 {
+		return nil, ErrListingUnavailable
+	}
+	return s.repo.Create(ctx, req, adminID, meta)
+}
+
+func (s *Service) Complete(ctx context.Context, pickupID uint64, req CompleteRequest, adminID uint64, meta auditlog.Meta) (*PickupDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	if pickupID == 0 || req.SettleAmountCent <= 0 {
+		return nil, ErrInvalidAmount
+	}
+	return s.repo.Complete(ctx, pickupID, req, adminID, meta)
+}
+
+func (s *Service) Cancel(ctx context.Context, pickupID uint64, reason string, adminID uint64, meta auditlog.Meta) error {
+	if s.repo == nil {
+		return ErrDependencyUnavailable
+	}
+	if pickupID == 0 || reason == "" {
+		return ErrPickupNotPickingUp
+	}
+	return s.repo.Cancel(ctx, pickupID, reason, adminID, meta)
+}
+
+func (s *Service) FindByID(ctx context.Context, id uint64) (*PickupDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	return s.repo.FindByID(ctx, id)
+}
+
+func (s *Service) ListAdmin(ctx context.Context, query AdminPickupQuery) (*PaginatedResult, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	return s.repo.ListAdmin(ctx, query)
+}
+
+func (s *Service) ListForSeller(ctx context.Context, ownerID uint64, query SellerPickupQuery) (*PaginatedResult, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	return s.repo.ListForSeller(ctx, ownerID, query)
+}
+
+func (s *Service) ListAvailableListings(ctx context.Context, keyword string, page, pageSize int) (*AvailableListingsResult, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	return s.repo.ListAvailableListings(ctx, keyword, page, pageSize)
+}