### fix: Aktualisiere Gradle und Kotlin Versionen

- **gradle-wrapper.properties:** Upgegrade von Gradle 9.4.1 zu 9.5.1.
- **libs.versions.toml:** Upgegrade von Kotlin 2.3.20 zu 2.4.0.
- **gradle.properties:** Entferne veraltete `kotlin.mpp.androidSourceSetLayoutVersion`.
- **.aiassistant/rules/Meldestelle-Guidelines.md:** Füge neue Guidelines hinzu.

Signed-off-by: StefanMoCoAt <stefan.mo.co@gmail.com>

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME