Topology view: always-on Internet/Proxy nodes + connect animation

[antoncxx]

Summary

• Internet and proxy nodes now always render in the topology graph, even with zero active connections — falls back to a dimmed, non-interactive placeholder proxy box ("no active connections") instead of disappearing entirely.
• Newly-appeared edges play a one-time connect animation (draw-in for plain edges, fade-in for dashed proxy-hop/egress/internet edges, chosen so the animation never distorts their fixed dash pattern) instead of just popping into place. Edges keyed by stable from→to identity so it never replays for connections that were already present.