Update models.json (#18586)

- Replace the active models-manager catalog with the deleted core
catalog contents.
- Replace stale hardcoded test model slugs with current bundled model
slugs.
- Keep this as a stacked change on top of the cleanup PR.

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

@@ -99,15 +99,14 @@ fn tool_search_output_tools(request: &ResponsesRequest, call_id: &str) -> Vec<Va
 }
 
 fn configure_search_capable_model(config: &mut Config) {
-    config.model = Some("gpt-5-codex".to_string());
-
     let mut model_catalog = bundled_models_response()
         .unwrap_or_else(|err| panic!("bundled models.json should parse: {err}"));
     let model = model_catalog
         .models
         .iter_mut()
-        .find(|model| model.slug == "gpt-5-codex")
-        .expect("gpt-5-codex exists in bundled models.json");
+        .find(|model| model.slug == "gpt-5.4")
+        .expect("gpt-5.4 exists in bundled models.json");
+    config.model = Some("gpt-5.4".to_string());
     model.supports_search_tool = true;
     config.model_catalog = Some(model_catalog);
 }