ReplaceOfflinePeers moves peers into d.offlinePeers but PeerStateByIP
only scanned d.peers. Callers (the local DNS filter via
localPeerConnectivity, embed.Client.IdentityForIP used by the
proxy's tunnel-peer validator) were treating known-but-offline peers
as unknown, which:
- causes the DNS filter to keep returning records pointing at peers
that have no live tunnel, AND
- makes the proxy's local-roster check deny a request from such a
peer rather than letting the cached management RPC carry the
authorisation decision.
Search both slices in PeerStateByIP. Adds a unit test for the IPv4
and IPv6 offline-match paths.
86e24a622d