fixing gradle build

core/core-domain/build.gradle.kts

@@ -5,14 +5,18 @@ plugins {
     alias(libs.plugins.kotlin.serialization)
 }
 
+kotlin {
+    compilerOptions {
+        freeCompilerArgs.add("-Xopt-in=kotlin.time.ExperimentalTime")
+    }
+}
+
 dependencies {
     // Stellt sicher, dass dieses Modul Zugriff auf die im zentralen Katalog
     // definierten Bibliotheken hat.
     api(projects.platform.platformDependencies)
 
-    // Kern-Abhängigkeiten für das Domänen-Modell.
-    // `api` wird verwendet, damit Services, die `core-domain` einbinden,
-    // diese Typen ebenfalls direkt nutzen können.
+    // Kern-Abhängigkeiten für das Domänen-Modul.
     api(libs.uuid)
     api(libs.kotlinx.serialization.json)
     api(libs.kotlinx.datetime)

core/core-domain/src/main/kotlin/at/mocode/core/domain/event/DomainEvent.kt

@@ -2,8 +2,9 @@ package at.mocode.core.domain.event
 
 import com.benasher44.uuid.Uuid
 import com.benasher44.uuid.uuid4
-import kotlinx.datetime.Clock
-import kotlinx.datetime.Instant
+import java.util.UUID
+import kotlin.time.Clock
+import kotlin.time.Instant
 
 /**
  * Base interface for all domain events in the system.
@@ -12,9 +13,9 @@ import kotlinx.datetime.Instant
 interface DomainEvent {
     val eventId: Uuid
     val aggregateId: Uuid
-    val eventType: String
+    val eventType: java.time.Instant
     val timestamp: Instant
-    val version: Long
+    val version: Int
 
     // OPTIMIZED: Added correlation and causation IDs for distributed tracing.
     /**
@@ -33,8 +34,8 @@ interface DomainEvent {
  */
 abstract class BaseDomainEvent(
     override val aggregateId: Uuid,
-    override val eventType: String,
-    override val version: Long,
+    override val eventType: java.time.Instant,
+    override val version: Int,
     override val eventId: Uuid = uuid4(),
     override val timestamp: Instant = Clock.System.now(),
     override val correlationId: Uuid? = null,

core/core-domain/src/main/kotlin/at/mocode/core/domain/model/BaseDto.kt

@@ -3,8 +3,8 @@ package at.mocode.core.domain.model
 import at.mocode.core.domain.serialization.KotlinInstantSerializer
 import at.mocode.core.domain.serialization.UuidSerializer
 import com.benasher44.uuid.Uuid
-import kotlinx.datetime.Clock
-import kotlinx.datetime.Instant
+import kotlin.time.Clock
+import kotlin.time.Instant
 import kotlinx.serialization.Serializable
 
 /**
@@ -49,7 +49,8 @@ data class ErrorDto(
 data class ApiResponse<T>(
     val data: T?,
     val success: Boolean,
-    val errors: List<ErrorDto> = emptyList(), // OPTIMIZED: Using structured ErrorDto
+    val errors: List<ErrorDto> = emptyList(),
+    @Serializable(with = KotlinInstantSerializer::class)
     val timestamp: Instant = Clock.System.now()
 ) {
     companion object {

core/core-domain/src/main/kotlin/at/mocode/core/domain/serialization/Serializers.kt

@@ -2,7 +2,7 @@ package at.mocode.core.domain.serialization
 
 import com.benasher44.uuid.Uuid
 import com.benasher44.uuid.uuidFrom
-import kotlinx.datetime.Instant
+import kotlin.time.Instant
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.LocalDateTime
 import kotlinx.datetime.LocalTime