Persist upstream Radar review artifacts

[yvette-carlisle]

Summary

• refreshed the deterministic openai/codex upstream review queue
• added source-backed bundles, upstream reviews, and upstream impacts for PRs 27526, 27488, 27443, and 27517
• added social_candidate/v1 handoffs for PRs 27488 and 27443 only; no social_post/v1 artifacts were written

Validation

• cargo run -p decodex --bin decodex -- radar bundle validate artifacts/github/bundles/openai-codex-pr-27526.json artifacts/github/bundles/openai-codex-pr-27488.json artifacts/github/bundles/openai-codex-pr-27443.json artifacts/github/bundles/openai-codex-pr-27517.json
• cargo run -p decodex --bin decodex -- radar validate artifacts/github/review-queue artifacts/github/bundles artifacts/github/reviews artifacts/github/impact artifacts/github/social-candidates
• cargo make check-site-content
• cargo make fmt
• cargo make lint-fix
• cargo make test