Function fqn_hash 

pub const fn fqn_hash(fqn: &str) -> u32

32-bit FNV-1a of an endpoint ref – the identity a trace marker and the SWD record carry for Violation::fqn (a string neither can hold).

FNV-1a because a decoder can recompute it in one line from the model’s endpoint list (scripts/read-violation-record.py does), with no table baked into the image.