Add use_agent_identity feature flag (#17385)

codex-rs/features/src/tests.rs

@@ -163,6 +163,24 @@ fn remote_control_is_under_development() {
     assert_eq!(Feature::RemoteControl.default_enabled(), false);
 }
 
+#[test]
+fn use_agent_identity_is_under_development() {
+    assert_eq!(Feature::UseAgentIdentity.stage(), Stage::UnderDevelopment);
+    assert_eq!(Feature::UseAgentIdentity.default_enabled(), false);
+}
+
+#[test]
+fn image_detail_original_feature_is_experimental_and_user_toggleable() {
+    let stage = Feature::ImageDetailOriginal.stage();
+
+    assert!(matches!(stage, Stage::Experimental { .. }));
+    assert_eq!(
+        stage.experimental_menu_name(),
+        Some("Original image detail")
+    );
+    assert_eq!(Feature::ImageDetailOriginal.default_enabled(), false);
+}
+
 #[test]
 fn collab_is_legacy_alias_for_multi_agent() {
     assert_eq!(feature_for_key("multi_agent"), Some(Feature::Collab));