feat: Add bus transport type to routing with Pareto ranking support

internal/routing/graph.go

@@ -141,13 +141,19 @@ func BuildGraphFromStations(stations []StationInfo) *Graph {
 
 		// Add synthetic edge: station <-> city hub
 		cityNode := cityNodes[si.CityCode]
+		tp := TransportTypeTrain
+		if si.CityCode == "c_airport" {
+			tp = TransportTypePlane
+		} else if si.CityCode == "c_bus" {
+			tp = TransportTypeBus
+		}
 		graph.AddEdge(&Edge{
 			From:       station,
 			To:         cityNode,
 			Kind:       EdgeKindSynthetic,
 			Duration:   300, // 5 min synthetic transfer
-			Transport:  "train",
-			TransportType: TransportTypeTrain,
+			Transport:  string(tp),
+			TransportType: tp,
 			IsTransfer: true,
 		})
 
@@ -157,8 +163,8 @@ func BuildGraphFromStations(stations []StationInfo) *Graph {
 			To:         station,
 			Kind:       EdgeKindSynthetic,
 			Duration:   300, // 5 min synthetic transfer
-			Transport:  "train",
-			TransportType: TransportTypeTrain,
+			Transport:  string(tp),
+			TransportType: tp,
 			IsTransfer: true,
 		})
 	}
@@ -172,13 +178,21 @@ func addSyntheticEdgesForNode(graph *Graph, node *Node) {
 	// Connect this node to city hubs in the same city via synthetic edges
 	for _, n := range graph.Nodes() {
 		if n.Type == NodeTypeCity && n.CityCode == node.CityCode {
+			// Determine transport type based on city code
+			tp := TransportTypeTrain
+			if node.CityCode == "c_airport" {
+				tp = TransportTypePlane
+			} else if node.CityCode == "c_bus" {
+				tp = TransportTypeBus
+			}
 			// Add synthetic edge from node to city hub
 			graph.AddEdge(&Edge{
 				From:       node,
 				To:         n,
 				Kind:       EdgeKindSynthetic,
 				Duration:   300, // 5 min synthetic transfer
-				Transport:  "train",
+				Transport:  string(tp),
+				TransportType: tp,
 				IsTransfer: true,
 			})
 
@@ -188,7 +202,8 @@ func addSyntheticEdgesForNode(graph *Graph, node *Node) {
 				To:         node,
 				Kind:       EdgeKindSynthetic,
 				Duration:   300, // 5 min synthetic transfer
-				Transport:  "train",
+				Transport:  string(tp),
+				TransportType: tp,
 				IsTransfer: true,
 			})
 		}
@@ -532,9 +547,10 @@ func (g *Graph) FindRoute(originID, destID string, opts SearchOptions, yclient .
 					From:       fromNode,
 					To:         toNode,
 					Duration:   seg.Duration,
-					Transport:  "train",
+					Transport:  string(TransportTypeTrain),
 					IsTransfer: seg.HasTransfers,
 					Kind:       EdgeKindReal,
+					TransportType: TransportTypeTrain,
 				})
 			}