Fix auto-review config compatibility across protocol and SDK (#19113)

## Why

This keeps the partial Guardian subagent -> Auto-review rename
forward-compatible across mixed Codex installations. Newer binaries need
to understand the new `auto_review` spelling, but they cannot write it
to shared `~/.codex/config.toml` yet because older CLI/app-server
bundles only know `user` and `guardian_subagent` and can fail during
config load before recovering.

The Python SDK had the opposite compatibility gap: app-server responses
can contain `approvalsReviewer: "auto_review"`, but the checked-in
generated SDK enum did not accept that value.

## What Changed

- Keep `ApprovalsReviewer::AutoReview` readable from both
`guardian_subagent` and `auto_review`, while serializing it as
`guardian_subagent` in both protocol crates.
- Update TUI Auto-review persistence tests so enabling Auto-review
writes `approvals_reviewer = "guardian_subagent"` while UI copy still
says Auto-review.
- Map managed/cloud `feature_requirements.auto_review` to the existing
`Feature::GuardianApproval` gate without adding a broad local
`[features].auto_review` key or changing config writes.
- Add `auto_review` to the Python SDK `ApprovalsReviewer` enum and cover
`ThreadResumeResponse` validation.

## Testing

- `cargo test -p codex-protocol approvals_reviewer`
- `cargo test -p codex-app-server-protocol approvals_reviewer`
- `cargo test -p codex-tui
update_feature_flags_enabling_guardian_selects_auto_review`
- `cargo test -p codex-tui
update_feature_flags_enabling_guardian_in_profile_sets_profile_auto_review_policy`
- `cargo test -p codex-core
feature_requirements_auto_review_disables_guardian_approval`
- `pytest
sdk/python/tests/test_client_rpc_methods.py::test_thread_resume_response_accepts_auto_review_reviewer`
- `git diff --check`

sdk/python/tests/test_client_rpc_methods.py

@@ -4,7 +4,12 @@ from pathlib import Path
 from typing import Any
 
 from codex_app_server.client import AppServerClient, _params_dict
-from codex_app_server.generated.v2_all import ThreadListParams, ThreadTokenUsageUpdatedNotification
+from codex_app_server.generated.v2_all import (
+    ApprovalsReviewer,
+    ThreadListParams,
+    ThreadResumeResponse,
+    ThreadTokenUsageUpdatedNotification,
+)
 from codex_app_server.models import UnknownNotification
 
 ROOT = Path(__file__).resolve().parents[1]
@@ -40,6 +45,34 @@ def test_generated_v2_bundle_has_single_shared_plan_type_definition() -> None:
     assert source.count("class PlanType(") == 1
 
 
+def test_thread_resume_response_accepts_auto_review_reviewer() -> None:
+    response = ThreadResumeResponse.model_validate(
+        {
+            "approvalPolicy": "on-request",
+            "approvalsReviewer": "auto_review",
+            "cwd": "/tmp",
+            "model": "gpt-5",
+            "modelProvider": "openai",
+            "sandbox": {"type": "dangerFullAccess"},
+            "thread": {
+                "cliVersion": "1.0.0",
+                "createdAt": 1,
+                "cwd": "/tmp",
+                "ephemeral": False,
+                "id": "thread-1",
+                "modelProvider": "openai",
+                "preview": "",
+                "source": "cli",
+                "status": {"type": "idle"},
+                "turns": [],
+                "updatedAt": 1,
+            },
+        }
+    )
+
+    assert response.approvals_reviewer is ApprovalsReviewer.auto_review
+
+
 def test_notifications_are_typed_with_canonical_v2_methods() -> None:
     client = AppServerClient()
     event = client._coerce_notification(
@@ -89,7 +122,9 @@ def test_unknown_notifications_fall_back_to_unknown_payloads() -> None:
 
 def test_invalid_notification_payload_falls_back_to_unknown() -> None:
     client = AppServerClient()
-    event = client._coerce_notification("thread/tokenUsage/updated", {"threadId": "missing"})
+    event = client._coerce_notification(
+        "thread/tokenUsage/updated", {"threadId": "missing"}
+    )
 
     assert event.method == "thread/tokenUsage/updated"
     assert isinstance(event.payload, UnknownNotification)