add infinite scroll to entries

lib/services/data_service/data_service_core.dart

@@ -18,6 +18,26 @@ class _LegFetchOptions {
     this.unallocatedOnly = false,
     this.networkFilter = const [],
   });
+
+  _LegFetchOptions copyWith({
+    int? limit,
+    String? sortBy,
+    int? sortDirection,
+    String? dateRangeStart,
+    String? dateRangeEnd,
+    bool? unallocatedOnly,
+    List<String>? networkFilter,
+  }) {
+    return _LegFetchOptions(
+      limit: limit ?? this.limit,
+      sortBy: sortBy ?? this.sortBy,
+      sortDirection: sortDirection ?? this.sortDirection,
+      dateRangeStart: dateRangeStart ?? this.dateRangeStart,
+      dateRangeEnd: dateRangeEnd ?? this.dateRangeEnd,
+      unallocatedOnly: unallocatedOnly ?? this.unallocatedOnly,
+      networkFilter: networkFilter ?? this.networkFilter,
+    );
+  }
 }
 
 class DataService extends ChangeNotifier {
@@ -397,11 +417,11 @@ class DataService extends ChangeNotifier {
     List<String> networkFilter = const [],
   }) async {
     _isLegsLoading = true;
+    final normalizedNetworks = networkFilter
+        .map((network) => network.trim())
+        .where((network) => network.isNotEmpty)
+        .toList();
     if (!append) {
-      final normalizedNetworks = networkFilter
-          .map((network) => network.trim())
-          .where((network) => network.isNotEmpty)
-          .toList();
       _lastLegsFetch = _LegFetchOptions(
         limit: limit,
         sortBy: sortBy,
@@ -437,6 +457,17 @@ class DataService extends ChangeNotifier {
       if (json is List) {
         final newLegs = json.map((e) => Leg.fromJson(e)).toList();
         _legs = append ? [..._legs, ...newLegs] : newLegs;
+        if (append) {
+          _lastLegsFetch = _lastLegsFetch.copyWith(
+            limit: _legs.length,
+            sortBy: sortBy,
+            sortDirection: sortDirection,
+            dateRangeStart: dateRangeStart,
+            dateRangeEnd: dateRangeEnd,
+            unallocatedOnly: unallocatedOnly,
+            networkFilter: normalizedNetworks,
+          );
+        }
         // Keep "load more" available as long as the server returns items; hide only on empty.
         _legsHasMore = newLegs.isNotEmpty;
       } else {