Fix CI test-compile failure on Java 11 by pinning JUnit Jupiter to a Java 11–compatible version

[Copilot]

The failing Actions job was caused by a test dependency/runtime mismatch: junit-jupiter:6.1.3 was resolved to class files targeting Java 17, while the matrix includes Java 11. This broke testCompile before tests could run.

• Root cause

  • CI matrix runs Java 11/17/21/25, but JUnit 6 artifacts in this build path require a newer bytecode level than Java 11 (61 vs 55).

• Change

  • Pin test dependency to a Java 11–compatible JUnit Jupiter release.
  • Scope remains test; no production code or test logic changed.

• Why this is minimal

  • Single-line dependency version change in pom.xml; no workflow or source changes required.

<dependency>
  <groupId>org.junit.jupiter</groupId>
  <artifactId>junit-jupiter</artifactId>
  <version>5.10.2</version>
  <scope>test</scope>
</dependency>