Wire auto-review runtime coordination

[shiny-code-bot]

Summary

• Hold a durable auto-review coordination lock for the lifetime of each detached background review task.
• Reconcile orphaned in-flight background auto-review runs on session startup when no live coordination lock remains.
• Add focused tests for lock lifetime and restart recovery.

Validation

• cargo test -p codex-core --test all automatic_background_review_holds_coordination_lock_until_completion -- --nocapture
• cargo test -p codex-core --test all session_startup_marks_orphaned_background_review_lost -- --nocapture
• cargo check -p codex-core
• cargo fmt --all --check
• git diff --check

Review notes

• Read-only agents reviewed the lifecycle and Every Code comparison. Follow-up findings were addressed: superseded-review lock retry, post-lock foreground cancellation recheck, and normalized recovery scope dedupe.
• Background auto-review could not complete on this branch because the diff exceeded the configured 120k character limit; the terminal run failed before findings for size only.