Function rope_tables 

pub fn rope_tables(
    head_dim: usize,
    max_seq: usize,
    theta: f64,
    device: &Device,
) -> Result<(Tensor<2>, Tensor<2>)>

Build Llama-style RoPE cos/sin tables for positions [0, max_seq).

Returns (cos, sin) each shaped [max_seq, head_dim] (interleaved cat([freqs, freqs]) layout). Shared by Chronos, Sundial, TimesFM, Toto.