models: simplify models.Node

Simplify the struct by removing un-used methods and outdated comments.

routing/payment_session_source.go

@@ -1,7 +1,6 @@
 package routing
 
 import (
-	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch"
@@ -102,17 +101,13 @@ func RouteHintsToEdges(routeHints [][]zpay32.HopHint, target route.Vertex) (
 			// we'll need to look at the next hint's start node. If
 			// we've reached the end of the hints list, we can
 			// assume we've reached the destination.
-			endNode := &models.Node{}
+			endNode := target
 			if i != len(routeHint)-1 {
-				endNode.AddPubKey(routeHint[i+1].NodeID)
-			} else {
-				targetPubKey, err := btcec.ParsePubKey(
-					target[:],
+				nodeID := routeHint[i+1].NodeID
+				copy(
+					endNode[:],
+					nodeID.SerializeCompressed(),
 				)
-				if err != nil {
-					return nil, err
-				}
-				endNode.AddPubKey(targetPubKey)
 			}
 
 			// Finally, create the channel edge from the hop hint
@@ -120,7 +115,7 @@ func RouteHintsToEdges(routeHints [][]zpay32.HopHint, target route.Vertex) (
 			// at the start of the channel.
 			edgePolicy := &models.CachedEdgePolicy{
 				ToNodePubKey: func() route.Vertex {
-					return endNode.PubKeyBytes
+					return endNode
 				},
 				ToNodeFeatures: lnwire.EmptyFeatureVector(),
 				ChannelID:      hopHint.ChannelID,