add loco legs panel

lib/components/pages/traction.dart

@@ -556,6 +556,7 @@ class _TractionPageState extends State<TractionPage> {
                         isSelected: _isSelected(loco),
                         onShowInfo: () => showTractionDetails(context, loco),
                         onOpenTimeline: () => _openTimeline(loco),
+                        onOpenLegs: () => _openLegs(loco),
                         onToggleSelect:
                             widget.selectionMode ? () => _toggleSelection(loco) : null,
                       ),
@@ -653,6 +654,14 @@ class _TractionPageState extends State<TractionPage> {
     await _refreshTraction();
   }
 
+  Future<void> _openLegs(LocoSummary loco) async {
+    final label = '${loco.locoClass} ${loco.number}'.trim();
+    await context.push(
+      '/traction/${loco.id}/legs',
+      extra: {'label': label},
+    );
+  }
+
   Widget _buildFilterInput(
     BuildContext context,
     EventField field,