Function finalize

src/python/runner.cpp:816–848

    }

    void finalize() {
        join_plugin_preload();

        if (!Py_IsInitialized()) {
            return;
        }

        set_gil_state_ready(false);

        if (get_main_thread_state()) {
            acquire_gil_main_thread();
        } else {
            LOG_WARN("No saved thread state, using PyGILState_Ensure");
            PyGILState_Ensure();
        }

        // Clear all callbacks that hold Python objects (nanobind::object)
        // This must be done while GIL is held since nanobind::object
        // destructor decrements Python reference counts
        lfs::training::ControlBoundary::instance().clear_all();

        // Clear frame callback if set
        clear_frame_callback();

        // Clear Python UI registries that hold nb::object references
        // These singletons would otherwise destroy nb::objects during
        // static destruction, after Python is gone
        invoke_python_cleanup();

        PyGC_Collect();

        // Skip Py_FinalizeEx() - nanobind static destructors need Python alive
    }

    bool was_python_used() {
        return get_main_thread_state() != nullptr || Py_IsInitialized();