Function zero_single_ssd_caches 

fn zero_single_ssd_caches(
    mamba_block: &Mamba3,
    batch: usize,
    n_virtual: usize,
    device: &Device,
) -> Mamba3SingleSsdCaches

Zero single-ssd caches sized from a [batch, sequence, d_model] input. (A missing cache defaults to the single-ssd pathway — ≈½ the SSD memory of double-ssd — for either rotation kind.)