## Why
A model requirement can force `auto_review` even when the requested reviewer is `user`. Persisting or sending that effective value back as an explicit choice loses the original selection, so removing the requirement cannot restore it on resume.
## What changed
- Retain `requested_approvals_reviewer` separately from the effective reviewer in configuration and thread settings, with a fallback for older histories.
- Restore the requested reviewer on resume while applying current model requirements and reviewer allowlists.
- Let ordinary TUI turns, continuations, retries, and forks inherit the server's reviewer instead of echoing its effective value as an explicit request.
- Preserve a worker's requested reviewer when reloading it rather than inheriting the sender's selection.
## Testing
Extend resume coverage for explicit `auto_review`, removal of a model requirement, and a tightened reviewer allowlist. Update TUI assertions for omitted reviewer overrides and verify worker reload preserves its reviewer.
GitOrigin-RevId: d8c9c3a7b89e55e63f0e8ae210d6a87cb5547933