Fix jacoco-maven-plugin version: 0.8.15 does not exist on Maven Central

The previous bump to 0.8.15 was incorrect — that version was never
published. The latest released version is 0.8.14 (Oct 2025).

Author: claude

pom.xml

@@ -184,7 +184,7 @@ SPDX-License-Identifier: MIT
 			<plugin>
 				<groupId>org.jacoco</groupId>
 				<artifactId>jacoco-maven-plugin</artifactId>
-				<version>0.8.15</version>
+				<version>0.8.14</version>
 				<executions>
 					<execution>
 						<id>prepare-agent</id>