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/common/streaming_sse.rs

@@ -601,7 +601,7 @@ data: {"type":"response.completed","response":{"id":"resp-1"}}
 
         let url = format!("{}/v1/responses", server.uri());
         let payload = serde_json::json!({
-            "model": "gpt-5.1",
+            "model": "gpt-5.4",
             "instructions": "test",
             "input": [{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "hello"}]}],
             "stream": true

codex-rs/core/tests/common/test_codex.rs

@@ -516,9 +516,9 @@ fn ensure_test_model_catalog(config: &mut Config) -> Result<()> {
     let mut model = bundled_models
         .models
         .iter()
-        .find(|candidate| candidate.slug == "gpt-5.1-codex")
+        .find(|candidate| candidate.slug == "gpt-5.2")
         .cloned()
-        .unwrap_or_else(|| panic!("missing bundled model gpt-5.1-codex"));
+        .unwrap_or_else(|| panic!("missing bundled model gpt-5.2"));
     model.slug = TEST_MODEL_WITH_EXPERIMENTAL_TOOLS.to_string();
     model.display_name = TEST_MODEL_WITH_EXPERIMENTAL_TOOLS.to_string();
     model.experimental_supported_tools = vec!["test_sync_tool".to_string()];