Add peer_id metrics and fix per-peer connection metrics

[swarna1101]

• peer_id metrics missing
• connection-to-peer metrics appear incorrect
• prefer per-peer libp2p host metrics over aggregated counters
• sent/recv messages per peer metrics are acceptable as-is

Acceptance: peer_id exposed in Prometheus, connection metrics validated against known peer set, per-peer series where aggregation hides disconnects.

add peer_id label to CL/mump2p send+recv RPC metrics per topic; track direct_cl_peers by peer_id; alert when a direct peer sends 0 messages over a window. Low cardinality risk - typically 1 CL + few mump2p peers per gateway.