fix: upgrade Mockito and JaCoCo for Java 25 compatibility

Mockito 5.20.0 and JaCoCo 0.8.12 both bundle an ASM version that does
not recognize Java 25 class file format (major version 69), causing
IllegalArgumentException at test time. Upgrading to versions released
after Java 25 GA resolves the issue.

- mockito: 5.20.0 → 5.23.0
- jacoco-maven-plugin: 0.8.12 → 0.8.14

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: carlossg

pom.xml

@@ -55,7 +55,7 @@
     <google.genai.version>1.44.0</google.genai.version>
     <protobuf.version>4.33.5</protobuf.version>
     <junit.version>5.11.4</junit.version>
-    <mockito.version>5.20.0</mockito.version>
+    <mockito.version>5.23.0</mockito.version>
     <java-websocket.version>1.6.0</java-websocket.version>
     <jackson.version>2.20.2</jackson.version>
     <okhttp.version>5.3.2</okhttp.version>
@@ -454,7 +454,7 @@
       <plugin>
         <groupId>org.jacoco</groupId>
         <artifactId>jacoco-maven-plugin</artifactId>
-        <version>0.8.12</version>
+        <version>0.8.14</version>
         <executions>
           <execution>
             <goals>