feat: add auto-review session configuration

[zfy0701]

Summary

• expose an ACP approvals_reviewer session option with User and Auto-review choices
• initialize the option from Codex thread state, including the legacy reviewer alias, and pass the selected reviewer to each turn
• document the new configuration surface and cover option updates, turn propagation, and existing approval-review events

Auto-review remains independent from approval and sandbox modes: it changes who reviews eligible escalation requests without granting additional permissions.

Closes #302

Validation

• npm run typecheck
• npm test (332 passed, 28 skipped)
• npm run build
• npm run codex-test -- -p "Reply with exactly: auto-review smoke test" -o summary (real Codex run, end_turn)

Created by Codex . GPT-5