feat: add /api/user/me endpoint for session restoration

internal/database/user_repository.go

@@ -227,3 +227,24 @@ func (r *UserRepository) UpdateUserRole(ctx context.Context, userID int, newRole
 	}
 	return nil
 }
+
+// GetUserByID находит пользователя по его ID.
+func (r *UserRepository) GetUserByID(ctx context.Context, userID int) (*models.User, error) {
+	user := &models.User{}
+	var userUUID string
+
+	query := "SELECT id, uuid, username, email, password_hash, role, created_at, updated_at FROM users WHERE id = $1"
+	err := r.DB.QueryRow(ctx, query, userID).Scan(
+		&user.ID, &userUUID, &user.Username, &user.Email, &user.PasswordHash, &user.Role, &user.CreatedAt, &user.UpdatedAt,
+	)
+
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, ErrUserNotFound
+		}
+		return nil, err
+	}
+
+	user.UUID, _ = uuid.Parse(userUUID)
+	return user, nil
+}