Handle no avatar, add delete avatar support

backend/internal/user/repository.go

@@ -179,6 +179,28 @@ func (r *Repository) SetAvatar(ctx context.Context, id int64, data []byte) error
 	return nil
 }
 
+func (r *Repository) DeleteAvatar(ctx context.Context, id int64) error {
+	query := "DELETE FROM avatars WHERE id = ?"
+	_, err := r.q.ExecContext(ctx, query, id)
+	if err != nil {
+		slog.Error("delete avatar", slog.String("op", "repo.DeleteAvatar"), slog.Int64("user_id", id), slog.Any("error", err))
+		return ErrInternal
+	}
+	return nil
+}
+
+// HasAvatar reports whether the user currently has an avatar stored.
+func (r *Repository) HasAvatar(ctx context.Context, id int64) (bool, error) {
+	query := "SELECT EXISTS(SELECT 1 FROM avatars WHERE id = ?)"
+	var exists bool
+	err := r.q.QueryRowContext(ctx, query, id).Scan(&exists)
+	if err != nil {
+		slog.Error("has avatar", slog.String("op", "repo.HasAvatar"), slog.Int64("user_id", id), slog.Any("error", err))
+		return false, ErrInternal
+	}
+	return exists, nil
+}
+
 func (r *Repository) CleanupUsers(ctx context.Context) error {
 	query := "DELETE FROM users WHERE activated_at IS NULL and created_at < ?"
 	_, err := r.q.ExecContext(ctx, query, time.Now().UTC().Add(-5*time.Minute))