const handleSubmit = async () => {
  const { date, time, timezone } = formData;

  // Build local datetime in selected timezone
  const localDT = DateTime.fromISO(
    `${date}T${time}`, 
    { zone: timezone }
  );

  // Validate it exists (handles DST gaps)
  if (!localDT.isValid) {
    showError(
      `${time} doesn't exist on ${date} in ${timezone} due to DST`
    );
    return;
  }

  // Send to server (server converts to UTC)
  await api.createEvent({
    scheduledDate: date,
    scheduledTime: time,
    eventTimezone: timezone,
    durationMinutes: 60
  });
};

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