Constant FORWARD_FAILURE_GRACE_MS 

pub(crate) const FORWARD_FAILURE_GRACE_MS: u64 = 60_000;

Grace period during which a forward failure against a live-process entry is presumed transient rather than proof the specific agent is gone — see should_evict_on_forward_failure. pub(crate) so muxspect_handlers’s verify-sender route can reuse the same real, already-tested staleness judgment for shared-registry entries instead of inventing its own threshold (see that module’s own doc comment for why).