Function baked_domain_from_c_abi 

pub fn baked_domain_from_c_abi(raw: u8) -> Option<u32>

Map the C/C++ ABI’s u8 domain argument onto the resolver’s baked rung.

0 → None (unset; the ladder decides), 255 (DOMAIN_ID_EXPLICIT_ZERO_C_ABI) → Some(0) (explicit zero), anything else → Some(n). Values in 233..=254 pass through so ExecutorConfig::try_resolve rejects them loudly (BootConfigError::DomainIdRange) instead of this edge inventing its own validation.