docs(policy): prefer Codex for autoreview

[steipete]

Summary

• exempt Codex-backed autoreview from the router/self-delegation gate
• keep the existing router guard for implementation, exploration, fixing, and git mechanics
• add the concise global rule to always prefer Codex for autoreview, independent of environment

Validation

• skill-cleaner root scan: 72/72 skills loaded, valid frontmatter, no duplicate names or bodies
• Codex autoreview (gpt-5.6-sol, high reasoning, fast tier): clean, no accepted/actionable findings

[clawsweeper]

ClawSweeper status: review started.

I am starting a fresh review of this pull request: docs(policy): prefer Codex for autoreview This is item 1/1 in the current shard. Shard 0/1.

This placeholder means the worker is alive and reading the current context. I will edit this same comment with the actual review when the claws are done clicking.

Crustacean status: shell secured, claws on keyboard, evidence pebbles being sorted.