add build step for flutter web, add persistent pagination in the traction list

lib/components/pages/new_entry/new_entry_page.dart

@@ -128,10 +128,6 @@ class _NewEntryPageState extends State<NewEntryPage> {
     }
   }
 
-  double _manualMilesFromInput(DistanceUnitService units) {
-    return units.milesFromInput(_mileageController.text) ?? 0;
-  }
-
   double _milesFromInputWithUnit(DistanceUnit unit) {
     return DistanceFormatter(unit)
             .parseInputMiles(_mileageController.text.trim()) ??
@@ -276,6 +272,7 @@ class _NewEntryPageState extends State<NewEntryPage> {
         ),
       ),
     );
+    if (!mounted) return;
     if (result != null) {
       final units = _distanceUnits(context);
       setState(() {
@@ -1536,43 +1533,6 @@ class _NewEntryPageState extends State<NewEntryPage> {
     );
   }
 
-  Widget _timeToggleBlock({
-    required String label,
-    required bool value,
-    required ValueChanged<bool?>? onChanged,
-    required String matchLabel,
-    required bool matchValue,
-    required ValueChanged<bool?>? onMatchChanged,
-    required bool showMatch,
-    Widget? picker,
-  }) {
-    return Column(
-      crossAxisAlignment: CrossAxisAlignment.start,
-      children: [
-        CheckboxListTile(
-          value: value,
-          onChanged: onChanged,
-          dense: true,
-          contentPadding: EdgeInsets.zero,
-          controlAffinity: ListTileControlAffinity.leading,
-          title: Text(label),
-        ),
-        if (showMatch)
-          CheckboxListTile(
-            value: matchValue,
-            onChanged: onMatchChanged,
-            dense: true,
-            contentPadding: const EdgeInsets.only(left: 12),
-            controlAffinity: ListTileControlAffinity.leading,
-            title: Text(matchLabel),
-          ),
-        if (picker != null) ...[
-          const SizedBox(height: 6),
-          picker,
-        ],
-      ],
-    );
-  }
 }
 
 class _UpperCaseTextFormatter extends TextInputFormatter {

lib/components/pages/new_entry/new_entry_submit_logic.dart

@@ -52,6 +52,7 @@ extension _NewEntrySubmitLogic on _NewEntryPageState {
     if (form == null) return;
     if (!form.validate()) return;
     if (!await _validateRequiredFields()) return;
+    if (!mounted) return;
     final routeStations = _routeResult?.calculatedRoute ?? [];
     final startVal = _useManualMileage
         ? _startController.text.trim()

lib/components/pages/new_traction.dart

@@ -84,6 +84,13 @@ class _NewTractionPageState extends State<NewTractionPage> {
       'traction_motors': TextEditingController(),
       'build_date': TextEditingController(),
     };
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      final data = context.read<DataService>();
+      if (data.locoClasses.isEmpty) {
+        data.fetchClassList();
+      }
+    });
   }
 
   @override
@@ -254,6 +261,10 @@ class _NewTractionPageState extends State<NewTractionPage> {
   @override
   Widget build(BuildContext context) {
     final isActive = _statusIsActive;
+    final data = context.watch<DataService>();
+    final classOptions = [...data.locoClasses]..sort(
+        (a, b) => a.toLowerCase().compareTo(b.toLowerCase()),
+      );
     final size = MediaQuery.of(context).size;
     final isNarrow = size.width < 720;
     final fieldWidth = isNarrow ? double.infinity : 340.0;
@@ -269,6 +280,89 @@ class _NewTractionPageState extends State<NewTractionPage> {
       double? widthOverride,
       String? Function(String?)? validator,
     }) {
+      // Special autocomplete for class field using existing loco classes.
+      if (key == 'class' && classOptions.isNotEmpty) {
+        return SizedBox(
+          width: widthOverride ?? fieldWidth,
+          child: Autocomplete<String>(
+            optionsBuilder: (TextEditingValue value) {
+              final query = value.text.trim().toLowerCase();
+              if (query.isEmpty) return classOptions;
+              return classOptions.where(
+                (c) => c.toLowerCase().contains(query),
+              );
+            },
+            onSelected: (selection) {
+              _controllers[key]?.text = selection;
+              _formKey.currentState?.validate();
+            },
+            fieldViewBuilder:
+                (context, textEditingController, focusNode, onFieldSubmitted) {
+              if (textEditingController.text != _controllers[key]?.text) {
+                WidgetsBinding.instance.addPostFrameCallback((_) {
+                  if (!mounted) return;
+                  if (textEditingController.text != _controllers[key]?.text) {
+                    textEditingController.value =
+                        _controllers[key]?.value ?? textEditingController.value;
+                  }
+                });
+              }
+              return TextFormField(
+                controller: textEditingController,
+                focusNode: focusNode,
+                decoration: InputDecoration(
+                  labelText: required ? '$label *' : label,
+                  helperText: helper,
+                  suffixText: suffixText,
+                  border: const OutlineInputBorder(),
+                ),
+                keyboardType: keyboardType,
+                maxLines: maxLines,
+                validator: (val) {
+                  if (required && (val == null || val.trim().isEmpty)) {
+                    return 'Required';
+                  }
+                  return validator?.call(val);
+                },
+                onChanged: (_) {
+                  _controllers[key]?.text = textEditingController.text;
+                  _formKey.currentState?.validate();
+                },
+                onFieldSubmitted: (_) => onFieldSubmitted(),
+              );
+            },
+            optionsViewBuilder: (context, onSelected, options) {
+              final opts = options.toList();
+              if (opts.isEmpty) return const SizedBox.shrink();
+              return Align(
+                alignment: Alignment.topLeft,
+                child: Material(
+                  elevation: 4,
+                  child: ConstrainedBox(
+                    constraints: BoxConstraints(
+                      maxHeight: 280,
+                      maxWidth: widthOverride ?? fieldWidth,
+                    ),
+                    child: ListView.builder(
+                      padding: EdgeInsets.zero,
+                      itemCount: opts.length,
+                      itemBuilder: (context, index) {
+                        final option = opts[index];
+                        return ListTile(
+                          dense: true,
+                          title: Text(option),
+                          onTap: () => onSelected(option),
+                        );
+                      },
+                    ),
+                  ),
+                ),
+              );
+            },
+          ),
+        );
+      }
+
       return SizedBox(
         width: widthOverride ?? fieldWidth,
         child: TextFormField(

lib/components/pages/traction/traction_page.dart

@@ -37,6 +37,9 @@ class _TractionPageState extends State<TractionPage> {
   final Map<String, TextEditingController> _dynamicControllers = {};
   final Map<String, String?> _enumSelections = {};
   bool _restoredFromPrefs = false;
+  static const int _pageSize = 100;
+  int _lastTractionOffset = 0;
+  String? _lastQuerySignature;
 
   @override
   void initState() {
@@ -59,6 +62,9 @@ class _TractionPageState extends State<TractionPage> {
   Future<void> _initialLoad() async {
     final data = context.read<DataService>();
     await _restoreSearchState();
+    if (_lastTractionOffset == 0 && data.traction.length > _pageSize) {
+      _lastTractionOffset = data.traction.length - _pageSize;
+    }
     data.fetchClassList();
     data.fetchEventFields();
     await _refreshTraction();
@@ -103,7 +109,29 @@ class _TractionPageState extends State<TractionPage> {
         dynamicFieldsUsed;
   }
 
-  Future<void> _refreshTraction({bool append = false}) async {
+  String _tractionQuerySignature(
+    Map<String, dynamic> filters,
+    bool hadOnly,
+  ) {
+    final sortedKeys = filters.keys.toList()..sort();
+    final filterSignature = sortedKeys
+        .map((key) => '$key=${filters[key]}')
+        .join('|');
+    final classQuery = (_selectedClass ?? _classController.text).trim();
+    return [
+      'class=$classQuery',
+      'number=${_numberController.text.trim()}',
+      'name=${_nameController.text.trim()}',
+      'mileageFirst=$_mileageFirst',
+      'hadOnly=$hadOnly',
+      'filters=$filterSignature',
+    ].join(';');
+  }
+
+  Future<void> _refreshTraction({
+    bool append = false,
+    bool preservePosition = true,
+  }) async {
     final data = context.read<DataService>();
     final filters = <String, dynamic>{};
     final name = _nameController.text.trim();
@@ -118,15 +146,49 @@ class _TractionPageState extends State<TractionPage> {
       }
     });
     final hadOnly = !_hasFilters;
+    final signature = _tractionQuerySignature(filters, hadOnly);
+    final queryChanged =
+        _lastQuerySignature != null && signature != _lastQuerySignature;
+    _lastQuerySignature = signature;
+
+    if (queryChanged && !append) {
+      _lastTractionOffset = 0;
+    }
+
+    final shouldPreservePosition = preservePosition &&
+        !append &&
+        !queryChanged &&
+        _lastTractionOffset > 0;
+
+    int limit;
+    int offset;
+    if (append) {
+      offset = data.traction.length;
+      limit = _pageSize;
+      _lastTractionOffset = offset;
+    } else if (shouldPreservePosition) {
+      offset = 0;
+      limit = _pageSize + _lastTractionOffset;
+    } else {
+      offset = 0;
+      limit = _pageSize;
+    }
+
     await data.fetchTraction(
       hadOnly: hadOnly,
       locoClass: _selectedClass ?? _classController.text.trim(),
       locoNumber: _numberController.text.trim(),
-      offset: append ? data.traction.length : 0,
+      offset: offset,
+      limit: limit,
       append: append,
       filters: filters,
       mileageFirst: _mileageFirst,
     );
+
+    if (!append && !shouldPreservePosition) {
+      _lastTractionOffset = 0;
+    }
+
     await _persistSearchState();
   }
 

lib/components/pages/traction/traction_persistence.dart

@@ -39,6 +39,16 @@ extension _TractionPersistence on _TractionPageState {
           enumValues[entry.key.toString()] = entry.value?.toString();
         }
       }
+      final lastOffsetRaw = decoded['lastOffset'];
+      if (lastOffsetRaw is int) {
+        _lastTractionOffset = lastOffsetRaw;
+      } else if (lastOffsetRaw is num) {
+        _lastTractionOffset = lastOffsetRaw.toInt();
+      }
+      final lastSig = decoded['querySignature']?.toString();
+      if (lastSig != null && lastSig.isNotEmpty) {
+        _lastQuerySignature = lastSig;
+      }
 
       for (final entry in dynamicValues.entries) {
         _dynamicControllers.putIfAbsent(
@@ -76,6 +86,8 @@ extension _TractionPersistence on _TractionPageState {
       'showAdvancedFilters': _showAdvancedFilters,
       'dynamic': _dynamicControllers.map((k, v) => MapEntry(k, v.text)),
       'enum': _enumSelections,
+      'lastOffset': _lastTractionOffset,
+      'querySignature': _lastQuerySignature,
     };
 
     try {