Persist Codex 0.139.0 and 0.140 alpha checkpoint handoff

[yvette-carlisle]

Summary

• refresh the Codex release-delta artifact to latest stable rust-v0.139.0 and latest prerelease rust-v0.140.0-alpha.2
• add a publishable social_candidate/v1 release-rollup handoff for stable 0.139.0
• add a terminal defer / needs_upstream_analysis social_candidate/v1 record for sparse 0.140.0-alpha.2
• keep unreviewed PR behavior release-note or PR-title scoped and hand off publication only to decodex-x-publisher

Evidence

• Official Codex changelog checked: https://developers.openai.com/codex/changelog
• Stable release: https://github.com/openai/codex/releases/tag/rust-v0.139.0
• Stable compare: openai/codex@rust-v0.138.0...rust-v0.139.0
• Prerelease checkpoint: https://github.com/openai/codex/releases/tag/rust-v0.140.0-alpha.2
• First-prerelease compare: openai/codex@rust-v0.139.0...rust-v0.140.0-alpha.2

Validation

• cargo run -p decodex --bin decodex -- radar validate artifacts/github/social-candidates site/src/content/release-deltas
• cargo make check-site-content
• cargo make fmt
• cargo make lint-fix
• cargo make test

Publisher handoff

• Stable candidate: artifacts/github/social-candidates/openai-codex-rust-v0-139-0-release-rollup.json
• Stable decision: publish
• Stable mode: release_rollup
• Stable idempotency key: x:decodexspace:openai-codex-rust-v0-139-0:stable138-stable139:release_rollup
• Prerelease candidate: artifacts/github/social-candidates/openai-codex-rust-v0-140-0-alpha-2-needs-upstream-analysis.json
• Prerelease decision: defer
• Prerelease reason: needs_upstream_analysis