Function ssm_replay_ring_bytes 

pub fn ssm_replay_ring_bytes(
    num_ssm_layers: usize,
    row_bytes: usize,
    k_ceiling: usize,
    mtp_state_slots: usize,
) -> usize

Replay-mode verify-window input ring: k_ceiling - 1 cached rows per covered slot per SSM layer (a partial accept replays at most K-1 tokens — rows 0..K-2; a full accept replays nothing). Reserved by preflight and allocated by SsmStatePool::new through THIS function so the two cannot disagree. Zero when speculation is off or the mode is Snapshot.