add timeline edit/delete

lib/components/pages/traction.dart

@@ -1,9 +1,12 @@
+import 'dart:convert';
+
 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/data_service.dart';
 import 'package:provider/provider.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 class TractionPage extends StatefulWidget {
   const TractionPage({
@@ -22,6 +25,7 @@ class TractionPage extends StatefulWidget {
 }
 
 class _TractionPageState extends State<TractionPage> {
+  static const String _prefsKey = 'traction_search_state_v1';
   final _classController = TextEditingController();
   final _classFocusNode = FocusNode();
   final _numberController = TextEditingController();
@@ -34,6 +38,7 @@ class _TractionPageState extends State<TractionPage> {
 
   final Map<String, TextEditingController> _dynamicControllers = {};
   final Map<String, String?> _enumSelections = {};
+  bool _restoredFromPrefs = false;
 
   @override
   void initState() {
@@ -48,17 +53,107 @@ class _TractionPageState extends State<TractionPage> {
       _initialised = true;
       _selectedKeys = {...widget.selectedKeys};
       WidgetsBinding.instance.addPostFrameCallback((_) {
-        final data = context.read<DataService>();
-        data.fetchClassList();
-        data.fetchEventFields();
-        _refreshTraction();
+        _initialLoad();
       });
     }
   }
 
+  Future<void> _initialLoad() async {
+    final data = context.read<DataService>();
+    await _restoreSearchState();
+    data.fetchClassList();
+    data.fetchEventFields();
+    await _refreshTraction();
+  }
+
+  Future<void> _restoreSearchState() async {
+    if (widget.selectionMode) return;
+    if (_restoredFromPrefs) return;
+    _restoredFromPrefs = true;
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final raw = prefs.getString(_prefsKey);
+      if (raw == null || raw.trim().isEmpty) return;
+      final decoded = jsonDecode(raw);
+      if (decoded is! Map) return;
+
+      final classText = decoded['classText']?.toString();
+      final numberText = decoded['number']?.toString();
+      final nameText = decoded['name']?.toString();
+      final selectedClass = decoded['selectedClass']?.toString();
+      final mileageFirst = decoded['mileageFirst'];
+      final showAdvanced = decoded['showAdvancedFilters'];
+
+      if (classText != null) _classController.text = classText;
+      if (numberText != null) _numberController.text = numberText;
+      if (nameText != null) _nameController.text = nameText;
+
+      final dynamicValues = <String, String>{};
+      final enumValues = <String, String?>{};
+      final dynamicRaw = decoded['dynamic'];
+      if (dynamicRaw is Map) {
+        for (final entry in dynamicRaw.entries) {
+          final key = entry.key.toString();
+          final val = entry.value?.toString() ?? '';
+          dynamicValues[key] = val;
+        }
+      }
+      final enumRaw = decoded['enum'];
+      if (enumRaw is Map) {
+        for (final entry in enumRaw.entries) {
+          enumValues[entry.key.toString()] = entry.value?.toString();
+        }
+      }
+
+      for (final entry in dynamicValues.entries) {
+        _dynamicControllers.putIfAbsent(
+          entry.key,
+          () => TextEditingController(text: entry.value),
+        );
+        _dynamicControllers[entry.key]?.text = entry.value;
+      }
+      for (final entry in enumValues.entries) {
+        _enumSelections[entry.key] = entry.value;
+      }
+
+      if (!mounted) return;
+      setState(() {
+        _selectedClass = (selectedClass != null && selectedClass.trim().isNotEmpty)
+            ? selectedClass
+            : null;
+        if (mileageFirst is bool) _mileageFirst = mileageFirst;
+        if (showAdvanced is bool) _showAdvancedFilters = showAdvanced;
+      });
+    } catch (_) {
+      // Ignore preference restore failures.
+    }
+  }
+
+  Future<void> _persistSearchState() async {
+    if (widget.selectionMode) return;
+    final payload = <String, dynamic>{
+      'classText': _classController.text,
+      'number': _numberController.text,
+      'name': _nameController.text,
+      'selectedClass': _selectedClass,
+      'mileageFirst': _mileageFirst,
+      'showAdvancedFilters': _showAdvancedFilters,
+      'dynamic': _dynamicControllers.map((k, v) => MapEntry(k, v.text)),
+      'enum': _enumSelections,
+    };
+
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      await prefs.setString(_prefsKey, jsonEncode(payload));
+    } catch (_) {
+      // Ignore persistence failures.
+    }
+  }
+
   @override
   void dispose() {
     _classController.removeListener(_onClassTextChanged);
+    _persistSearchState();
     _classController.dispose();
     _classFocusNode.dispose();
     _numberController.dispose();
@@ -111,6 +206,7 @@ class _TractionPageState extends State<TractionPage> {
       filters: filters,
       mileageFirst: _mileageFirst,
     );
+    await _persistSearchState();
   }
 
   void _clearFilters() {
@@ -547,12 +643,14 @@ class _TractionPageState extends State<TractionPage> {
     return _selectedKeys.contains(keyVal);
   }
 
-  void _openTimeline(LocoSummary loco) {
+  Future<void> _openTimeline(LocoSummary loco) async {
     final label = '${loco.locoClass} ${loco.number}'.trim();
-    context.push(
+    await context.push(
       '/traction/${loco.id}/timeline',
       extra: {'label': label},
     );
+    if (!mounted) return;
+    await _refreshTraction();
   }
 
   Widget _buildFilterInput(