add loco legs panel

lib/components/pages/loco_legs.dart

@@ -0,0 +1,119 @@
+import 'package:flutter/material.dart';
+import 'package:mileograph_flutter/components/legs/leg_card.dart';
+import 'package:mileograph_flutter/objects/objects.dart';
+import 'package:mileograph_flutter/services/data_service.dart';
+import 'package:provider/provider.dart';
+
+class LocoLegsPage extends StatefulWidget {
+  const LocoLegsPage({
+    super.key,
+    required this.locoId,
+    required this.locoLabel,
+  });
+
+  final int locoId;
+  final String locoLabel;
+
+  @override
+  State<LocoLegsPage> createState() => _LocoLegsPageState();
+}
+
+class _LocoLegsPageState extends State<LocoLegsPage> {
+  bool _includeNonPowering = false;
+  late Future<List<Leg>> _future;
+
+  @override
+  void initState() {
+    super.initState();
+    _future = _fetch();
+  }
+
+  Future<List<Leg>> _fetch() {
+    return context.read<DataService>().fetchLegsForLoco(
+          widget.locoId,
+          includeNonPowering: _includeNonPowering,
+        );
+  }
+
+  Future<void> _refresh() async {
+    final items = await _fetch();
+    if (!mounted) return;
+    setState(() {
+      _future = Future.value(items);
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final titleLabel =
+        widget.locoLabel.trim().isEmpty ? 'Loco ${widget.locoId}' : widget.locoLabel;
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('Legs · $titleLabel'),
+        actions: [
+          IconButton(
+            tooltip: 'Refresh',
+            onPressed: _refresh,
+            icon: const Icon(Icons.refresh),
+          ),
+        ],
+      ),
+      body: SafeArea(
+        child: Column(
+          children: [
+            Padding(
+              padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
+              child: Card(
+                child: SwitchListTile(
+                  title: const Text('Include non-powering (dead-in-tow)'),
+                  subtitle: const Text('Off by default'),
+                  value: _includeNonPowering,
+                  onChanged: (val) {
+                    setState(() {
+                      _includeNonPowering = val;
+                      _future = _fetch();
+                    });
+                  },
+                ),
+              ),
+            ),
+            Expanded(
+              child: FutureBuilder<List<Leg>>(
+                future: _future,
+                builder: (context, snapshot) {
+                  final items = snapshot.data ?? const <Leg>[];
+                  final isLoading =
+                      snapshot.connectionState == ConnectionState.waiting;
+
+                  if (isLoading && items.isEmpty) {
+                    return const Center(child: CircularProgressIndicator());
+                  }
+
+                  if (!isLoading && items.isEmpty) {
+                    return const Center(
+                      child: Padding(
+                        padding: EdgeInsets.all(16.0),
+                        child: Text('No legs found for this loco.'),
+                      ),
+                    );
+                  }
+
+                  return RefreshIndicator(
+                    onRefresh: _refresh,
+                    child: ListView.builder(
+                      padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
+                      physics: const AlwaysScrollableScrollPhysics(),
+                      itemCount: items.length,
+                      itemBuilder: (context, index) => LegCard(leg: items[index]),
+                    ),
+                  );
+                },
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+