Function resolve_priority 

pub fn resolve_priority(consumer: Option<&Consumer>, route: &Route) -> u8

Resolve a request’s load-shedding priority class (DW-016). This is the documented PRIORITY-RESOLVER seam: consumer (once known) overrides the route, the route overrides the default. Today authentication is not wired (DW-019/DW-020), so the caller passes None and priority is purely route-level; once authN identifies the consumer, pass Some(consumer) here and its priority wins over the route’s — no other change to the shedding path is needed.