fix: add error handling for CashboxExportScheduler subscription processing

- Wrap runOne(subscription) in try/catch to ensure one subscription failure doesn't block remaining subscriptions
- Log failed subscriptions with new 'cashbox_export_subscription_run_fail' event
- Add new LOGEVENT type for subscription run failures
- Add test to verify second subscription processes even when first fails (continues processing independently)
- All 7 tests passing: 6 original + 1 new failure handling test

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

myteamwallet_backend/src/database/logging/model/logging-event.type.ts

@@ -31,6 +31,7 @@ export type LOGEVENT =
   | 'recurring_transaction_update'
   | 'recurring_transaction_delete'
   | 'recurring_transaction_run'
-  | 'cashbox_export_subscription_run';
+  | 'cashbox_export_subscription_run'
+  | 'cashbox_export_subscription_run_fail';
 
 export type LOGLEVEL = 'FATAL' | 'ERROR' | 'WARN' | 'INFO' | 'DEBUG' | 'TRACE';