add loco legs panel

lib/main.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:dynamic_color/dynamic_color.dart';
 import 'package:mileograph_flutter/components/pages/calculator.dart';
 import 'package:mileograph_flutter/components/pages/calculator_details.dart';
+import 'package:mileograph_flutter/components/pages/loco_legs.dart';
 import 'package:mileograph_flutter/components/pages/loco_timeline.dart';
 import 'package:mileograph_flutter/components/pages/new_entry.dart';
 import 'package:mileograph_flutter/components/pages/new_traction.dart';
@@ -123,6 +124,27 @@ class MyApp extends StatelessWidget {
                 );
               },
             ),
+            GoRoute(
+              path: '/traction/:id/legs',
+              builder: (_, state) {
+                final idParam = state.pathParameters['id'];
+                final locoId = int.tryParse(idParam ?? '') ?? 0;
+                final extra = state.extra;
+                String label = state.uri.queryParameters['label'] ?? '';
+                if (extra is Map && extra['label'] is String) {
+                  label = extra['label'] as String;
+                } else if (extra is String && extra.isNotEmpty) {
+                  label = extra;
+                }
+                if (label.trim().isEmpty) {
+                  label = 'Loco $locoId';
+                }
+                return LocoLegsPage(
+                  locoId: locoId,
+                  locoLabel: label,
+                );
+              },
+            ),
             GoRoute(
               path: '/traction/new',
               builder: (context, state) => const NewTractionPage(),