Account settings changes refreshed every peer, even an IPv6 group toggle
that re-addresses a few, and the refresh goroutine got the request context,
so it could be cancelled when the handler returned. Group paths that
reconcile IPv6 addresses only walked the changed group, so peers reaching a
re-addressed peer through its other groups missed the new address.
The IPv6 reconcile now returns the peers whose address changed and callers
pass them as changed peers. An IPv6-only settings change dispatches affected
peers, adding every IPv6 holder on a range change since the interface prefix
comes from the range. IPv4 range and account-wide changes keep the full
refresh with a detached context.
Maycon Santos