### feat: verbessere DTO-Handling und füge Feature-Flag hinzu

- **NennungViewModel:** Definiere lokales `NennungDto` zur Optimierung der Backend-Response-Verarbeitung.
- **MailPollingService:** Ergänze Bedingung für Scheduler-Aktivierung (`ConditionalOnProperty`).
- **.env & application.yaml:** Füge `MAIL_POLLING_ENABLED` als Feature-Flag hinzu.
- **Dependencies:** Refaktor Import-Reihenfolge für Konsistenz.

backend/services/mail/mail-service/src/main/kotlin/at/mocode/mail/service/MailPollingService.kt

@@ -10,9 +10,9 @@ import jakarta.mail.Session
 import jakarta.mail.internet.InternetAddress
 import org.jetbrains.exposed.v1.jdbc.SchemaUtils
 import org.jetbrains.exposed.v1.jdbc.transactions.transaction
-import org.springframework.transaction.annotation.Transactional
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Value
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty
 import org.springframework.boot.context.event.ApplicationReadyEvent
 import org.springframework.context.event.EventListener
 import org.springframework.mail.SimpleMailMessage
@@ -20,6 +20,7 @@ import org.springframework.mail.javamail.JavaMailSender
 import org.springframework.scheduling.annotation.EnableScheduling
 import org.springframework.scheduling.annotation.Scheduled
 import org.springframework.stereotype.Service
+import org.springframework.transaction.annotation.Transactional
 import java.util.*
 import kotlin.uuid.ExperimentalUuidApi
 import kotlin.uuid.Uuid
@@ -27,6 +28,7 @@ import kotlin.uuid.Uuid
 @OptIn(ExperimentalUuidApi::class)
 @Service
 @EnableScheduling
+@ConditionalOnProperty(value = ["mail.polling.enabled"], havingValue = "true", matchIfMissing = false)
 class MailPollingService(
   private val mailSender: JavaMailSender,
   private val nennungRepository: NennungRepository,

backend/services/mail/mail-service/src/main/kotlin/at/mocode/mail/service/persistence/NennungRepository.kt

@@ -5,9 +5,9 @@ package at.mocode.mail.service.persistence
 import org.jetbrains.exposed.v1.core.eq
 import org.jetbrains.exposed.v1.jdbc.insert
 import org.jetbrains.exposed.v1.jdbc.selectAll
+import org.jetbrains.exposed.v1.jdbc.transactions.transaction
 import org.jetbrains.exposed.v1.jdbc.update
 import org.springframework.stereotype.Repository
-import org.jetbrains.exposed.v1.jdbc.transactions.transaction
 import org.springframework.transaction.annotation.Transactional
 import kotlin.uuid.ExperimentalUuidApi
 import kotlin.uuid.Uuid

backend/services/mail/mail-service/src/main/resources/application.yaml

@@ -44,3 +44,8 @@ management:
     web:
       exposure:
         include: "health,info,prometheus"
+
+# Feature-Flags
+mail:
+  polling:
+    enabled: ${MAIL_POLLING_ENABLED:false}