Function is_retryable_route_open 

pub fn is_retryable_route_open(code: &str) -> bool

Whether a route.open refusal carrying code may be retried in place within the caller’s deadline, or is terminal for the target as named.

This lives beside the codes because every consumer with its own connection layer needs the same answer: a copied list breaks loudly on a renamed code and silently on an added one. The SDKs call this; the golden decision_tables.json (route_open_retryable) is the record the daemon and every SDK are tested against, and the test in golden_json.rs holds this function to it.

Unknown codes are terminal: a refusal this crate has never heard of must not be retried on the strength of a match-all arm.