test: AI coverage improvements (run 28770027319)

[github-actions]

Summary

Automated PR from the AI Coverage Agent (run 28770027319).

Changes may include

• New Test*.java classes for production classes with low JaCoCo branch or instruction coverage
• Additional test methods in existing test classes targeting uncovered branches
• Tests written with JUnit 5 (@Test, @ParameterizedTest) and AssertJ assertions

Review checklist

• CI passes (Build, Spotless, Static Analysis)
• New tests assert meaningful behaviour (not trivial getters or tautological assertions)
• JaCoCo coverage metrics have improved or stayed the same