Persist Codex alpha10 alpha11 checkpoint handoffs

[yvette-carlisle]

Summary

• Add terminal defer / needs_upstream_analysis social_candidate/v1 records for rust-v0.140.0-alpha.10 and rust-v0.140.0-alpha.11.
• Preserve adjacent prerelease lineage, compare URLs, PR-title gap lists, and media caveats.
• Record that deterministic release-delta refresh still selected rust-v0.140.0-alpha.9 despite GitHub release metadata showing alpha10/alpha11 as newer public prereleases.

Validation

• decodex radar validate artifacts/github/social-candidates artifacts/social/x
• cargo make fmt
• cargo make lint-fix
• cargo make test

Notes

• No X publication was attempted.
• Both candidates are terminal defer records and should not be handed to decodex-x-publisher until upstream source review fills the named gaps.

[yvette-carlisle]

Superseded by #352, which landed the alpha.10/alpha.11 defer records along with the alpha.13 release-delta refresh and 2026-06-11 Codex app candidate.