Endpoint identity documented the IPv6 scope identifier as an established
component alongside family, address and port. The server specification does
list the zone, but its remaining-unknowns section records that multi-zone
behavior could not be tested on a single-host platform, so no evidence settles
how a reference server compares scoped addresses. Presenting the choice as
verified compatibility overstated what is known, which the crate's own guidance
forbids.
Say what it is instead: a deliberate policy taken under a recorded unknown. Two
peers reachable at the same link-local address in different zones are genuinely
different peers, so treating the zone as identity is the conservative reading —
the failure it prevents is one peer closing another's session, and the failure
it risks is a scoped client having to reopen. The excluded flow label is
labelled the same way, and `irtt-server` guidance now carries the rule so the
echo slice reuses this comparison rather than inventing a second one.
Behavior is unchanged; this is documentation and a test comment.