Reserve X publication for Codex PR 26469

[yvette-carlisle]

Summary

• Adds and consumes a PR-visible X publish reservation for the checked social_candidate/v1 openai-codex-pr-26469.
• Adds the published social_post/v1 record for the live @decodexspace post.
• Records checked-record, open-PR, account, profile/timeline, search-supporting, daily-cap, timeline, and permalink evidence.

Publication

• https://x.com/decodexspace/status/2063833413266845827
• Text-only practical_explainer; no media attached because the source-backed startup latency sample and direct PR link carry the reader value.

Validation

• cargo run -p decodex --bin decodex -- radar validate artifacts/github/social-candidates artifacts/social/x

Notes

• Repository labels codex and codex-automation are not present; applied kind:chore.