Persist upstream Radar review artifacts

[yvette-carlisle]

Summary

• Refresh deterministic upstream Radar queue for openai/codex.
• Add source-backed reviews, impact classifications, and social candidates for PR #28122 and PR #26662.
• Add deterministic GitHub change bundles for both selected subjects.

Reviewed subjects

• [codex] exec-server honors remote environment cwd and shell openai/codex#28122: remote exec preserves environment cwd as PathUri and uses selected environment native shell.
• feat(app-server): filter threads by parent openai/codex#26662: app-server thread/list.parentThreadId lists direct spawned children from persisted spawn edges.

Validation

• decodex radar bundle validate artifacts/github/bundles/openai-codex-pr-28122.json
• decodex radar bundle validate artifacts/github/bundles/openai-codex-pr-26662.json
• cargo run -p decodex --bin decodex -- radar validate artifacts/github/review-queue/openai-codex-latest.json artifacts/github/bundles/openai-codex-pr-28122.json artifacts/github/bundles/openai-codex-pr-26662.json artifacts/github/reviews/openai-codex-pr-28122.review.json artifacts/github/reviews/openai-codex-pr-26662.review.json artifacts/github/impact/openai-codex-pr-28122.json artifacts/github/impact/openai-codex-pr-26662.json artifacts/github/social-candidates/openai-codex-pr-28122.json artifacts/github/social-candidates/openai-codex-pr-26662.json
• cargo make fmt
• cargo make lint-fix
• cargo make test