[Demo] BUG: ECR stub not allowing official fields

[tkim602]

Fixes #11

Demo provenance

This live replay reproduces a historical open-source issue and candidate patch, then runs it through the deployed frozen PatchCheck verifier.

• Original issue: BUG: ECR stub not allowing official fields getmoto/moto#8484
• Upstream reference fix: ECR: Lifecycle Policies() now support the tagPatternList-parameter getmoto/moto#8551
• Original repository: https://github.com/getmoto/moto
• Base commit: getmoto/moto@a57c5c8
• Model exposure: FT06 training example
• Frozen reference outcome: UNSAFE
• Candidate patch SHA-256: 06aaf1a1895cfbf042f862fca9b5895b90f50084894411dabfcd0ee81f6c10ec

GitHub canonicalizes unchanged hunk context when rendering the pull request diff; the base file and candidate code edit are reproduced exactly.

Selection was fixed in docs/demo-cases.json before inference. PatchCheck is advisory and does not merge or approve this patch.

[github-actions]

PatchCheck review

Model signal: HIGH
Model risk percentile: 85.2

Code-change findings

• medium: production Python changed without test-file changes (moto/ecr/policy_validation.py)

Fingerprints

• base_sha: 57c8b70384df46abcf32f3053430286922ea8a97
• head_sha: eb60da4a3e3802d5bde71103eb738c853f5740d3

Review-priority signal only; not a safety approval.