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

horses/horses-infrastructure/src/main/kotlin/at/mocode/horses/infrastructure/persistence/HorseRepositoryImpl.kt

@@ -9,6 +9,7 @@ import kotlinx.datetime.Clock
 import org.jetbrains.exposed.sql.*
 import org.jetbrains.exposed.sql.SqlExpressionBuilder.eq
 import org.jetbrains.exposed.sql.statements.UpdateBuilder
+import org.springframework.stereotype.Repository
 
 /**
  * PostgreSQL implementation of the HorseRepository using Exposed ORM.
@@ -16,6 +17,7 @@ import org.jetbrains.exposed.sql.statements.UpdateBuilder
  * This implementation provides database operations for horse entities,
  * mapping between the domain model (DomPferd) and the database table (HorseTable).
  */
+@Repository
 class HorseRepositoryImpl : HorseRepository {
 
     override suspend fun findById(id: Uuid): DomPferd? = DatabaseFactory.dbQuery {