Allow Guardian scoring for required computer-use models (#40967)

## Why

Models that require automatic review previously skipped Guardian v2 risk scoring
entirely, even when Guardian was limited to computer-use tools. That scope cannot
use a low-risk result to approve unrelated tools, so the blanket skip is
unnecessary.

## What changed

- Retain Guardian v2 risk scoring for required-review models in
  `ComputerUseOnly` scope while continuing to skip it in standard scope.
- Preserve strict automatic approval review for Node REPL-backed tools, including
  when classification fails.

## Testing

Added coverage for low-risk, high-risk, and invalid classifications across the
Node REPL and computer-use REPL paths, plus an unrelated MCP tool.

GitOrigin-RevId: ee38fabf82e196df0ae13b4216b5892be9b799cf

codex-rs/ext/guardian-v2/src/async_scorer/extension.rs

@@ -525,12 +525,15 @@ impl GuardianV2Extension {
             }
         };
         let parent_model = input.thread_store.get::<ModelInfo>();
-        if parent_model.as_ref().is_some_and(|model| {
-            config
-                .config_layer_stack
-                .requirements()
-                .auto_review_required_for_model(&model.slug)
-        }) {
+        // Computer-use-only scores cannot approve other tools for required models.
+        if guardian_config.review_scope != GuardianV2ReviewScope::ComputerUseOnly
+            && parent_model.as_ref().is_some_and(|model| {
+                config
+                    .config_layer_stack
+                    .requirements()
+                    .auto_review_required_for_model(&model.slug)
+            })
+        {
             input.thread_store.remove::<SecurityRiskScore>();
             return;
         }

codex-rs/ext/guardian-v2/src/async_scorer/extension_tests.rs

@@ -1901,7 +1901,7 @@ async fn contributor_persists_nested_code_mode_action_with_score() -> Result<()>
 }
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-async fn contributor_skips_models_requiring_managed_guardian_review() -> Result<()> {
+async fn contributor_skips_required_models_in_standard_scope() -> Result<()> {
     skip_if_no_network!(Ok(()));
 
     let thread_server = responses::start_mock_server().await;
@@ -1961,6 +1961,16 @@ async fn contributor_skips_models_requiring_managed_guardian_review() -> Result<
         })
         .await;
 
+    let mut guardian_config = thread_store
+        .get::<crate::async_scorer::config::GuardianV2Config>()
+        .expect("Guardian v2 should have initialized")
+        .as_ref()
+        .clone();
+    guardian_config.review_scope = GuardianV2ReviewScope::Standard {
+        sandboxed_exec_commands: false,
+    };
+    thread_store.insert(guardian_config);
+
     let mut model_info = test
         .thread_manager
         .get_models_manager()