feat(core) Smart approvals on (#10286)

## Summary
Turn on Smart Approvals by default

## Testing
 - [x] Updated unit tests

codex-rs/core/tests/suite/client.rs

@@ -320,7 +320,7 @@ async fn resume_includes_initial_messages_and_sends_prior_items() {
         .expect("prior assistant message");
     let pos_permissions = messages
         .iter()
-        .position(|(role, text)| role == "developer" && text.contains("`approval_policy`"))
+        .position(|(role, text)| role == "developer" && text.contains("<permissions instructions>"))
         .expect("permissions message");
     let pos_user_instructions = messages
         .iter()

codex-rs/core/tests/suite/collaboration_instructions.rs

@@ -83,7 +83,7 @@ async fn no_collaboration_instructions_by_default() -> Result<()> {
     let input = req.single_request().input();
     let dev_texts = developer_texts(&input);
     assert_eq!(dev_texts.len(), 1);
-    assert!(dev_texts[0].contains("`approval_policy`"));
+    assert!(dev_texts[0].contains("<permissions instructions>"));
 
     Ok(())
 }

codex-rs/core/tests/suite/permissions_messages.rs

@@ -34,7 +34,7 @@ fn permissions_texts(input: &[serde_json::Value]) -> Vec<String> {
                 .first()?
                 .get("text")?
                 .as_str()?;
-            if text.contains("`approval_policy`") {
+            if text.contains("<permissions instructions>") {
                 Some(text.to_string())
             } else {
                 None
@@ -439,7 +439,7 @@ async fn permissions_message_includes_writable_roots() -> Result<()> {
         &sandbox_policy,
         AskForApproval::OnRequest,
         &Policy::empty(),
-        false,
+        true,
         test.config.cwd.as_path(),
     )
     .into_text();