refactor: Migrate from monolithic to modular architecture

### **Service-Implementation**
- [ ] **Tag 1**: Members-Service REST-API implementieren
- [ ] **Tag 2**: Database-Migrations und Repository-Layer
- [ ] **Tag 3**: Event-Publishing nach Kafka aktivieren
- [ ] **Tag 4**: Horses-Service analog implementieren
- [ ] **Tag 5**: Integration-Tests für beide Services
- [ ] **Tag 6-7**: Events-Service und Masterdata-Service

infrastructure/messaging/messaging-config/src/main/kotlin/at/mocode/infrastructure/messaging/config/KafkaConfig.kt

@@ -0,0 +1,40 @@
+package at.mocode.infrastructure.messaging.config
+
+import org.apache.kafka.clients.producer.ProducerConfig
+import org.apache.kafka.common.serialization.StringSerializer
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.kafka.core.DefaultKafkaProducerFactory
+import org.springframework.kafka.core.KafkaTemplate
+import org.springframework.kafka.core.ProducerFactory
+import org.springframework.kafka.support.serializer.JsonSerializer
+
+/**
+ * Kafka configuration for event publishing.
+ */
+@Configuration
+class KafkaConfig {
+
+    @Value("\${spring.kafka.bootstrap-servers:localhost:9092}")
+    private lateinit var bootstrapServers: String
+
+    @Bean
+    fun producerFactory(): ProducerFactory<String, Any> {
+        val configProps = mapOf(
+            ProducerConfig.BOOTSTRAP_SERVERS_CONFIG to bootstrapServers,
+            ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG to StringSerializer::class.java,
+            ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG to JsonSerializer::class.java,
+            ProducerConfig.ACKS_CONFIG to "all",
+            ProducerConfig.RETRIES_CONFIG to 3,
+            ProducerConfig.ENABLE_IDEMPOTENCE_CONFIG to true,
+            ProducerConfig.MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION to 1
+        )
+        return DefaultKafkaProducerFactory(configProps)
+    }
+
+    @Bean
+    fun kafkaTemplate(): KafkaTemplate<String, Any> {
+        return KafkaTemplate(producerFactory())
+    }
+}