Constant RELATION_DIGEST 

pub const RELATION_DIGEST: [Felt; 4];

RELATION_DIGEST = Poseidon2::hash_elements([PROTOCOL_ID, CIRCUIT_COMMITMENT]).

Compile-time constant binding the Fiat-Shamir transcript to the Miden VM AIR. Must match the constants in crates/lib/core/asm/sys/vm/mod.masm.