Update Codex release publishing gates

[yvette-carlisle]

Summary

• Refresh the Codex release-delta cursor to stable rust-v0.137.0 and prerelease rust-v0.138.0-alpha.4.
• Tighten release/prerelease publishing rules: stable-to-stable release channel, adjacent prerelease channel, quote-only live quote-eligible prerelease posts, clickable PR URLs, and media fail-closed behavior.
• Clarify that @CodexReleases and @Codex_Changelog are historical style inspiration only: recurring automation must not live-read them, use their coverage as evidence, or decide publish/skip state from whether they posted.
• Add app 26.602 and alpha3 -> alpha4 publishable candidates plus deleted/failed alpha4 post lifecycle records so future quote lineage cannot reuse bad attempts.
• Add social_post post_lifecycle validation in Rust, Python contract helper, and JSON schema.
• Compact the publisher skill surfaces into a shared social-release gate reference; plugin-eval now reports A/100 for codex-release-analysis, x-post-publisher, and x-post-quality-system with good active budgets.

Validation

• cargo make fmt-check
• cargo test -p decodex radar::tests
• cargo make check-site-content
• python3 -m py_compile scripts/github/contracts.py
• jq empty scripts/github/social_post.schema.json artifacts/github/social-candidates/openai-codex-app-26-602.json artifacts/github/social-candidates/openai-codex-rust-v0-138-0-alpha-4-prerelease-delta.json artifacts/social/x/posts/2026-06-05/*.json site/src/content/release-deltas/openai-codex-latest.json
• python3 /Users/x/.codex/plugins/cache/hack-ink/playbook/0.3.0/scripts/semantic_drift_audit.py --rev HEAD
• node /Users/x/.codex/plugins/cache/openai-curated/plugin-eval/e2d08a2e/scripts/plugin-eval.js analyze dev/skills/codex-release-analysis --format markdown
• node /Users/x/.codex/plugins/cache/openai-curated/plugin-eval/e2d08a2e/scripts/plugin-eval.js analyze dev/skills/x-post-publisher --format markdown
• node /Users/x/.codex/plugins/cache/openai-curated/plugin-eval/e2d08a2e/scripts/plugin-eval.js analyze dev/skills/x-post-quality-system --format markdown

Notes

• Related Codex app media is local at /Users/x/.codex/decodex/social-media/codex-app-26-602.png; image binaries are intentionally not committed.
• Codex App automations codex-release-checkpoint-publisher and decodex-x-publisher were updated locally with the same benchmark-account boundary and shared-reference prompt path, and remain PAUSED until this PR is reviewed/landed.