Add antipodal point unit test for distance calculator

[Pygmalion69]

Summary

• extend the distance calculator tests to cover the Point-based overload
• add an antipodal scenario to validate cross-hemisphere calculations with tolerance
• introduce a reflective helper to instantiate library Point objects for testing

Testing

• ./gradlew test (fails: Failed to find Build Tools revision 35.0.0)

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https://chatgpt.com/codex/tasks/task_e_68fa4af147e48327b324cb591467b88f