[Refactor] core 모듈 테스트 커버리지 100% 향상

[seonghobae]

core 모듈의 테스트 커버리지를 100%로 끌어올리기 위해 부족했던 테스트 코드(test_env_paths.py, test_telemetry.py 등)를 추가하였으며, IPv6 등 기존 기능의 검증 로직도 보완했습니다.

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PR created automatically by Jules for task 227962273569673869 started by @seonghobae

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