/**
     * Adds a new interval rule to the rule list.
     *
     * @param from the start time in HH:MM format
     * @param to the end time in HH:MM format
     * @param days comma-separated list of days (1=Sunday, 7=Saturday)
     * @param delay the delay in milliseconds to apply during this interval
     */
    public void addIntervalRule(final String from, final String to, final String days, final long delay) {