[moelomda]

Invalid --cov-fail-under values such as nan, -inf, and -1 currently run the tests and then raise an internal error in coverage.py. Reject them during argument parsing with a usage error before test collection. Preserve valid thresholds from 0 through 100 and the existing error for values above 100.

Add CLI regressions that check invalid values cannot trigger collection, cover valid boundaries, and document the accepted range.

Validation: seven regression cases fail on the unchanged base. The updated applicable suite passes with 228 passed, 3 Windows-only skips, and the Docker/Redis/Celery integration case excluded because its prerequisites are unavailable. tox check and the documentation HTML build pass. Documentation linkcheck was stopped after GitHub rate limits; it also reported an existing broken changelog link. The full Python matrix was not run locally.

Prepared and verified with Codex assistance.

Hosted CI is awaiting maintainer approval (Tests run); no hosted test results are available yet.

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