fix: close lifecycle terminal states

[Anionix]

Summary

• reject failure transitions after REPORTED
• freeze dataset expected counts
• persist BENCHMARKED to REPORTED after report generation
• require REPORTED evidence for release packaging
• place the lifecycle contract beside workflow mutations

Verification

• 7 focused model/report/release tests passed
• workflow fixture test passed
• git diff --check

Fixes #67

[chatgpt-codex-connector]

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