fix: address code review findings

internal/routing/graph.go

@@ -418,7 +418,7 @@ func (g *Graph) FindRoute(originID, destID string, opts SearchOptions, closedSta
 			newDurationWithMCT := newDuration + transferTime
 
 			// Check if we've visited this node with fewer transfers
-			visKey := current.nodeID
+			visKey := nextNode.ID
 			if existingTransfers, ok := visited[visKey]; ok {
 				if current.transfers+1 > existingTransfers {
 					// Already visited this node with fewer transfers, skip
@@ -880,7 +880,7 @@ type SearchResult struct {
 // route in all three metrics simultaneously. Routes are sorted according to the RankingMode
 // in SearchOptions: "fastest" (default, by duration), "fewest_transfers" (by transfers),
 // or "cheapest" (by cost).
-func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions) []*Itinerary {
+func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions, closedStations map[string]bool, neighbors map[string][]storage.StationNeighbor) []*Itinerary {
 	// Run multiple searches with different strategies to find diverse routes
 	var allItineraries []*Itinerary
 
@@ -889,7 +889,7 @@ func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions) []
 		optsCopy := opts
 		optsCopy.MaxTransfers = maxTransfers
 
-		result := g.FindRoute(originID, destID, optsCopy, nil, nil)
+		result := g.FindRoute(originID, destID, optsCopy, closedStations, neighbors)
 		if result != nil && result.TotalDuration > 0 {
 			allItineraries = append(allItineraries, result)
 		}