feat: add detected models and second-model review

[jeremymcs]

Summary

• discover model choices from installed Codex and Claude CLIs while preserving saved selections
• add an opt-in second-model review selector and run the chosen reviewer before commit/push
• persist review settings and cover discovery, configuration, storage, UI wiring, and babysitter orchestration

Verification

• npm run test:all — 836 passed
• npm run check
• npm run lint
• npm run build
• npm run build:public-docs
• git diff --check

Critical-path coverage: focused regression tests cover reviewer selection, model propagation, failure handling, and merge-conflict review-before-commit ordering.

Notes

• The repository-required Claude /simplify command was attempted twice with Opus, but stalled without output and was terminated; it made no worktree changes.
• Screenshot not attached: this environment did not produce an uploadable browser artifact for the Settings control.

[github-actions]

✅ Documentation Updated

This PR includes documentation changes:

docs/public/agent-dispatch.md
docs/public/configuration.md

The docs build succeeded. Changes will be deployed to GitHub Pages when merged to main.