Function parse_decode_ring_slots 

pub fn parse_decode_ring_slots(s: &str) -> Result<Option<usize>, String>

SSOT parse for the --ssm-decode-ring-slots value: auto (None — size it from free memory at preflight) or an explicit 0..=8.

validate_serve_args and publish_kernel_flags both go through THIS, so what the CLI accepts and what it publishes cannot drift.