add ability for non admins to add new traction, pending approval. Various QoL updates

lib/components/pages/traction/traction_pending_page.dart

@@ -0,0 +1,140 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:mileograph_flutter/components/traction/traction_card.dart';
+import 'package:mileograph_flutter/objects/objects.dart';
+import 'package:mileograph_flutter/services/api_service.dart';
+import 'package:provider/provider.dart';
+
+class TractionPendingPage extends StatefulWidget {
+  const TractionPendingPage({super.key});
+
+  @override
+  State<TractionPendingPage> createState() => _TractionPendingPageState();
+}
+
+class _TractionPendingPageState extends State<TractionPendingPage> {
+  bool _isLoading = false;
+  String? _error;
+  List<LocoSummary> _locos = const [];
+
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addPostFrameCallback((_) => _load());
+  }
+
+  Future<void> _load() async {
+    setState(() {
+      _isLoading = true;
+      _error = null;
+    });
+    try {
+      final api = context.read<ApiService>();
+      final params = '?limit=200&offset=0';
+      final json = await api.get('/loco/pending$params');
+      if (json is List) {
+        setState(() {
+          _locos = json
+              .whereType<Map>()
+              .map((e) => LocoSummary.fromJson(
+                    e.map((k, v) => MapEntry(k.toString(), v)),
+                  ))
+              .toList();
+        });
+      } else {
+        setState(() {
+          _error = 'Unexpected response';
+          _locos = const [];
+        });
+      }
+    } catch (e) {
+      setState(() {
+        _error = e.toString();
+        _locos = const [];
+      });
+    } finally {
+      if (mounted) {
+        setState(() {
+          _isLoading = false;
+        });
+      }
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        leading: IconButton(
+          icon: const Icon(Icons.arrow_back),
+          onPressed: () => Navigator.of(context).maybePop(),
+        ),
+        title: const Text('Pending traction'),
+      ),
+      body: RefreshIndicator(
+        onRefresh: _load,
+        child: _buildBody(context),
+      ),
+    );
+  }
+
+  Widget _buildBody(BuildContext context) {
+    if (_isLoading && _locos.isEmpty) {
+      return const Center(child: CircularProgressIndicator());
+    }
+    if (_error != null) {
+      return ListView(
+        padding: const EdgeInsets.all(16),
+        children: [
+          Text(
+            'Failed to load pending traction: $_error',
+            style: Theme.of(context)
+                .textTheme
+                .bodyMedium
+                ?.copyWith(color: Theme.of(context).colorScheme.error),
+          ),
+          const SizedBox(height: 12),
+          FilledButton.icon(
+            onPressed: _load,
+            icon: const Icon(Icons.refresh),
+            label: const Text('Retry'),
+          ),
+        ],
+      );
+    }
+    if (_locos.isEmpty) {
+      return ListView(
+        padding: const EdgeInsets.all(16),
+        children: const [
+          Text('No pending traction found.'),
+        ],
+      );
+    }
+    return ListView.builder(
+      padding: const EdgeInsets.all(12),
+      itemCount: _locos.length,
+      itemBuilder: (context, index) {
+        final loco = _locos[index];
+        return Padding(
+          padding: const EdgeInsets.symmetric(vertical: 6.0),
+          child: TractionCard(
+            loco: loco,
+            selectionMode: false,
+            isSelected: false,
+            onShowInfo: () => showTractionDetails(
+              context,
+              loco,
+              onActionComplete: _load,
+            ),
+            onOpenTimeline: () => context.push(
+              '/traction/${loco.id}/timeline',
+              extra: {'label': '${loco.locoClass} ${loco.number}'.trim()},
+            ),
+            onOpenLegs: () => context.push('/traction/${loco.id}/legs'),
+            onActionComplete: _load,
+          ),
+        );
+      },
+    );
+  }
+}