Update Kotlin API version and langchain4j dependency

Added Kotlin API version 1.9 and updated langchain4j to 1.0.0-alpha1 in `pom.xml` for compatibility and new features. Configured Kotlin compiler with multi-platform support and aligned language and API versions for consistency.

Author: Konstantin Pavlov

pom.xml

@@ -46,6 +46,7 @@
         <kotlin.code.style>official</kotlin.code.style>
         <java.version>17</java.version>
         <kotlin.version>2.1.0</kotlin.version>
+        <kotlin.api.version>1.9</kotlin.api.version>
         <kotlin.compiler.jvmTarget>${java.version}</kotlin.compiler.jvmTarget>
         <maven.compiler.release>${java.version}</maven.compiler.release>
         <maven.compiler.source>${java.version}</maven.compiler.source>
@@ -54,7 +55,7 @@
         <finchly.version>0.1.1</finchly.version>
         <junit.version>5.11.4</junit.version>
         <kotlinx.version>1.10.1</kotlinx.version>
-        <langchain4j.version>0.36.2</langchain4j.version>
+        <langchain4j.version>1.0.0-alpha1</langchain4j.version>
         <mockito-kotlin.version>5.4.0</mockito-kotlin.version>
         <mockito.version>5.15.2</mockito.version>
         <slf4j.version>2.0.16</slf4j.version>
@@ -276,6 +277,9 @@
                         <!--<arg>-Werror</arg>-->
                     </args>
                     <javaParameters>true</javaParameters>
+                    <multiPlatform>true</multiPlatform>
+                    <languageVersion>${kotlin.api.version}</languageVersion>
+                    <apiVersion>${kotlin.api.version}</apiVersion>
                 </configuration>
             </plugin>