Versuche

frontend/shared/build.gradle.kts

@@ -20,7 +20,7 @@ plugins {
 kotlin {
   val enableWasm = providers.gradleProperty("enableWasm").orNull == "true"
 
-  jvmToolchain(21)
+  jvmToolchain(25)
 
   // JVM Target für Desktop
   jvm()
@@ -101,7 +101,7 @@ kotlin {
 // KMP Compile-Optionen
 tasks.withType<KotlinCompile> {
   compilerOptions {
-    jvmTarget.set(JvmTarget.JVM_21)
+    jvmTarget.set(JvmTarget.JVM_25)
     freeCompilerArgs.addAll(
       "-opt-in=kotlin.RequiresOptIn"
     )