ax(node): rename loop variable p to peer in GetPeersByScore

AX Principle 1 — predictable names over short names. Single-letter
variable p in GetPeersByScore replaced with peer, matching the type
it holds and the usage in surrounding code.

Co-Authored-By: Charon <charon@lethean.io>

pkg/node/peer.go

@@ -464,8 +464,8 @@ func (r *PeerRegistry) GetPeersByScore() []*Peer {
 	defer r.mutex.RUnlock()
 
 	peers := make([]*Peer, 0, len(r.peers))
-	for _, p := range r.peers {
-		peers = append(peers, p)
+	for _, peer := range r.peers {
+		peers = append(peers, peer)
 	}
 
 	// Sort by score descending