Upgrade Gradle and add iOS targets

- Upgraded Gradle wrapper to version 8.5.
- Updated Gradle build scripts and configurations.
- Added iOS targets (iosX64, iosArm64, iosSimulatorArm64) to the Kotlin Multiplatform setup.
- Configured shared iOS source sets.
- Bumped project version to 3.1.0.
- Updated JDK version to 21 in project settings.
- Removed kotlinScripting.xml.
- Added runConfigurations.xml and AndroidProjectSystem.xml.

.idea/gradle.xml

@@ -4,8 +4,9 @@
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
-        <option name="distributionType" value="WRAPPED" />
+        <option name="testRunner" value="CHOOSE_PER_TEST" />
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="#GRADLE_LOCAL_JAVA_HOME" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />