infra: add ai code reviews

[JuArce]

Add Claude and Codex for code reviews

Description

Allow Claude and Codex to perform code reviews.

Type of change

• New feature

Checklist

• “Hotfix” to testnet, everything else to staging
• Linked to Github Issue
• This change depends on code or research by an external entity
  • Acknowledgements were updated to give credit
• Unit tests added
• This change requires new documentation.
  • Documentation has been added/updated.
• This change is an Optimization
  • Benchmarks added/run
• Has a known issue
  • Link to the open issue addressing it
• If your PR changes the Operator compatibility (Ex: Upgrade prover versions)
  • This PR adds compatibility for operator for both versions and do not change crates/docs/examples
  • This PR updates batcher and docs/examples to the newer version. This requires the operator are already updated to be compatible

[github-actions]

Codex Code Review

1. High – Supply chain risk from mutable reusable-workflow ref
   Both workflows call external reusable workflows by tag (@v1.0.1) instead of an immutable commit SHA. If that tag is moved or compromised, arbitrary workflow code can run in this repo context with passed secrets.

   • pr_review_codex.yml:18
   • pr_review_claude.yml:18

2. High (conditional) – Secret exposure path via /issue_comment trigger
   The job runs on issue_comment and passes API secrets. If the called reusable workflow checks out or executes PR-head code (especially from forks), a collaborator comment (/codex or /claude) could trigger secret exfiltration from attacker-controlled changes. The risk depends on callee workflow internals, but this PR introduces the exposure path.

   • pr_review_codex.yml:6, :14, :38
   • pr_review_claude.yml:6, :14, :38

3. Medium – No explicit token permission scoping
   No permissions: block is set. This leaves GITHUB_TOKEN scope to repo/org defaults, which may be broader than required.

   • pr_review_codex.yml:1
   • pr_review_claude.yml:1

No significant performance issues found in this diff.