feat(marketing): user profile update, ad placement management, logo limits

- Add PUT /auth/profile endpoint for nickname and avatar updates
- Add ad_placements table and CRUD admin API for managing ad units
- Add GET /marketing/ad-config public API for mini-program to fetch ad config
- Reduce logo limit from 10 to 3 per user, add 2MB file size validation

Made-with: Cursor

internal/marketing/repository/ad_placement_repo.go

@@ -0,0 +1,76 @@
+package repository
+
+import (
+	"errors"
+	"fmt"
+
+	"gorm.io/gorm"
+
+	"wx_service/internal/marketing/model"
+)
+
+var ErrAdPlacementNotFound = errors.New("ad placement not found")
+
+type AdPlacementRepository struct {
+	db *gorm.DB
+}
+
+func NewAdPlacementRepository(db *gorm.DB) *AdPlacementRepository {
+	return &AdPlacementRepository{db: db}
+}
+
+func (r *AdPlacementRepository) Create(p *model.AdPlacement) error {
+	if err := r.db.Create(p).Error; err != nil {
+		return fmt.Errorf("create ad placement: %w", err)
+	}
+	return nil
+}
+
+func (r *AdPlacementRepository) Update(p *model.AdPlacement) error {
+	if err := r.db.Save(p).Error; err != nil {
+		return fmt.Errorf("update ad placement: %w", err)
+	}
+	return nil
+}
+
+func (r *AdPlacementRepository) Delete(id uint) error {
+	tx := r.db.Delete(&model.AdPlacement{}, id)
+	if tx.Error != nil {
+		return fmt.Errorf("delete ad placement: %w", tx.Error)
+	}
+	if tx.RowsAffected == 0 {
+		return ErrAdPlacementNotFound
+	}
+	return nil
+}
+
+func (r *AdPlacementRepository) FindByID(id uint) (*model.AdPlacement, error) {
+	var p model.AdPlacement
+	err := r.db.First(&p, id).Error
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrAdPlacementNotFound
+		}
+		return nil, fmt.Errorf("find ad placement: %w", err)
+	}
+	return &p, nil
+}
+
+func (r *AdPlacementRepository) ListAll() ([]model.AdPlacement, error) {
+	var list []model.AdPlacement
+	err := r.db.Order("id DESC").Find(&list).Error
+	return list, err
+}
+
+func (r *AdPlacementRepository) FindByMiniProgramAndType(miniProgramID uint, adType string) (*model.AdPlacement, error) {
+	var p model.AdPlacement
+	err := r.db.Where("mini_program_id = ? AND ad_type = ? AND status = 1", miniProgramID, adType).
+		First(&p).Error
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrAdPlacementNotFound
+		}
+		return nil, fmt.Errorf("find ad placement by type: %w", err)
+	}
+	return &p, nil
+}