refactoring:

1. Update MemberRepositoryImpl: replace DatabaseFactory.dbQuery calls with explicit Exposed transaction{} and remove the non-existent import; add necessary ExperimentalTime opt-ins and fix Clock usages.
2. Inspect members-infrastructure MemberTable.kt to add missing ExperimentalTime opt-ins and adjust types if needed.
3. Rebuild to surface any remaining Exposed API or import errors and fix them.
4. Verify members-api compiles and that endpoints remain intact; provide final summary.

core/core-domain/src/commonMain/kotlin/at/mocode/core/domain/serialization/KotlinxInstantSerializer.kt

@@ -0,0 +1,26 @@
+@file:OptIn(kotlin.time.ExperimentalTime::class)
+package at.mocode.core.domain.serialization
+
+import kotlinx.datetime.Instant
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+/**
+ * Serializer for kotlinx.datetime.Instant.
+ * Uses ISO-8601 string representation.
+ */
+object KotlinxInstantSerializer : KSerializer<Instant> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("KotlinxInstant", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: Instant) {
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): Instant {
+        return Instant.parse(decoder.decodeString())
+    }
+}

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

@@ -31,6 +31,8 @@ object KotlinInstantSerializer : KSerializer<Instant> {
     }
 }
 
+// Note: Serializer for kotlinx.datetime.Instant is defined in a separate file
+
 /**
  * Serializer für UUID Objekte.
  * Konvertiert UUID zu/von String-Repräsentation.