docs(prover): correct prove() exit code doc comment

[eviehoward]

Summary

Corrects the prove() doc comment which incorrectly described exit code 1 as
firing on "critical or high findings." The prover has no severity grades — exit
code 1 fires on any unaccepted finding.

Related Issue

Closes#2394

Changes

• Corrected exit code descriptions in crates/openshell-prover/src/lib.rs:31-32

Testing

• mise run pre-commit passes
• Unit tests added/updated — not applicable, doc comment only
• E2E tests added/updated — not applicable

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Architecture docs updated — not applicable

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[eviehoward]

I have read the DCO document and I hereby sign the DCO.

[matthewgrossman]

recheck

[elezar]

Thanks @eviehoward.

Your changes missed the fact that the function never returns 2 (at least in the current version) and returns the error code wrapped in a Result. This seems to have been incorrect from the start.

Instead of a review back and forth, I have addressed this in the branch.

[elezar]

/ok-to-test 761f54a

[elezar]

Thanks for the documentation fix. While validating the prove() behavior, we identified a few non-blocking cleanup candidates that may be useful follow-up work if you are interested:

• refactor(prover): separate outcome evaluation from rendering #2411 — centralize prover outcome evaluation and make the renderers presentation-only
• refactor(prover): remove legacy unused reachability constraints #2412 — remove legacy reachability constraints that are no longer consumed by active queries
• refactor(prover): define and surface accepted-risk provenance #2413 — define and surface accepted-risk provenance, including accepted_by

These are follow-up candidates only and do not block this PR.

[eviehoward]

I will take a look now, thank you!