Refuse repeated decoded identities in retained review observations #468

🤖 Generated by the Agentic Engineer

Problem

The review-thread counter and default-branch classifier parse ambiguous JSON before detecting repeated decoded keys. A later value can erase an unresolved thread or failed conclusion and produce an empty result.

Reproduced offline against freshly fetched main with a valid control. Inspected guidance and repositories were not executed, and no inference or provider test was launched.

Acceptance criteria

Refuse repeated decoded object keys before semantic parsing across raw documents and paginated containers; retain ordinary single/multipage controls, native exit semantics and failed-read UNKNOWN. Do not change native CI access boundaries. Size: S.

Part of #51. Related roadmap: #38.