Function py_batch_simulate 

pub(crate) fn py_batch_simulate<'py>(
    py: Python<'py>,
    model_name: &str,
    n_steps: usize,
    current_trace: PyReadonlyArray1<'py, f64>,
) -> PyResult<Py<PyAny>>

Run a named neuron model for n_steps with a current trace, returning voltage trace + spike indices. Entire simulation in Rust.