feat: Add NOTIFICATION_TEST_MODE for cron testing

When NOTIFICATION_TEST_MODE=true, cron runs every minute instead of
at the scheduled time. Useful for testing email notifications.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/cron/calendar/index.js

@@ -16,16 +16,34 @@ const parseNotificationTime = () => {
   };
 };
 
+/**
+ * Check if test mode is enabled
+ * @returns {boolean}
+ */
+const isTestMode = () => {
+  return process.env.NOTIFICATION_TEST_MODE === 'true';
+};
+
 /**
  * Start the calendar notification cron job
  */
 export const startCalendarNotificationCron = () => {
-  const { hour, minute } = parseNotificationTime();
+  let cronExpression;
+  let description;
 
-  // Cron expression: minute hour * * * (every day at specified time)
-  const cronExpression = `${minute} ${hour} * * *`;
+  if (isTestMode()) {
+    // Test mode: run every minute
+    cronExpression = '* * * * *';
+    description = 'každú minútu (TEST MODE)';
+    logger.warn('NOTIFICATION_TEST_MODE je zapnutý - cron beží každú minútu!');
+  } else {
+    // Production mode: run at specified time
+    const { hour, minute } = parseNotificationTime();
+    cronExpression = `${minute} ${hour} * * *`;
+    description = `${hour}:${minute.padStart(2, '0')} každý deň`;
+  }
 
-  logger.info(`Nastavujem cron pre kalendárne notifikácie: ${cronExpression} (${hour}:${minute.padStart(2, '0')} každý deň)`);
+  logger.info(`Nastavujem cron pre kalendárne notifikácie: ${cronExpression} (${description})`);
 
   const task = cron.schedule(cronExpression, async () => {
     logger.info('Cron job spustený - kontrolujem zajtrajšie udalosti');
@@ -41,7 +59,7 @@ export const startCalendarNotificationCron = () => {
     timezone: 'Europe/Bratislava',
   });
 
-  logger.success(`Kalendárny notifikačný cron naplánovaný na ${hour}:${minute.padStart(2, '0')} (Europe/Bratislava)`);
+  logger.success(`Kalendárny notifikačný cron naplánovaný: ${description} (Europe/Bratislava)`);
 
   return task;
 };