feat(marketing): add user logo management module

Users can now save uploaded logos to the backend (marketing_user_logos table),
avoiding repeated uploads. Includes CRUD endpoints: list, save, delete with
a per-user limit of 10 logos.

Made-with: Cursor

internal/marketing/repository/user_logo_repo.go

@@ -0,0 +1,65 @@
+package repository
+
+import (
+	"errors"
+	"fmt"
+
+	"gorm.io/gorm"
+
+	"wx_service/internal/marketing/model"
+)
+
+var ErrUserLogoNotFound = errors.New("user logo not found")
+
+type UserLogoRepository struct {
+	db *gorm.DB
+}
+
+func NewUserLogoRepository(db *gorm.DB) *UserLogoRepository {
+	return &UserLogoRepository{db: db}
+}
+
+func (r *UserLogoRepository) Create(logo *model.UserLogo) error {
+	if err := r.db.Create(logo).Error; err != nil {
+		return fmt.Errorf("create user logo: %w", err)
+	}
+	return nil
+}
+
+func (r *UserLogoRepository) FindByUser(userID uint) ([]model.UserLogo, error) {
+	var logos []model.UserLogo
+	err := r.db.Where("user_id = ?", userID).Order("id DESC").Find(&logos).Error
+	if err != nil {
+		return nil, fmt.Errorf("list user logos: %w", err)
+	}
+	return logos, nil
+}
+
+func (r *UserLogoRepository) FindByID(id, userID uint) (*model.UserLogo, error) {
+	var logo model.UserLogo
+	err := r.db.Where("id = ? AND user_id = ?", id, userID).First(&logo).Error
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrUserLogoNotFound
+		}
+		return nil, fmt.Errorf("find user logo: %w", err)
+	}
+	return &logo, nil
+}
+
+func (r *UserLogoRepository) Delete(id, userID uint) error {
+	tx := r.db.Where("id = ? AND user_id = ?", id, userID).Delete(&model.UserLogo{})
+	if tx.Error != nil {
+		return fmt.Errorf("delete user logo: %w", tx.Error)
+	}
+	if tx.RowsAffected == 0 {
+		return ErrUserLogoNotFound
+	}
+	return nil
+}
+
+func (r *UserLogoRepository) CountByUser(userID uint) (int64, error) {
+	var count int64
+	err := r.db.Model(&model.UserLogo{}).Where("user_id = ?", userID).Count(&count).Error
+	return count, err
+}