feat: enhance inventory management with category and location filters

flutter/lib/features/inventory/presentation/inventory_screen.dart

@@ -17,6 +17,7 @@ class InventoryScreen extends ConsumerWidget {
     (value: 'nameAsc', label: context.l10n.inventorySortNameAsc),
     (value: 'bestBeforeAsc', label: context.l10n.inventorySortBestBeforeAsc),
     (value: 'bestBeforeDesc', label: context.l10n.inventorySortBestBeforeDesc),
+    (value: 'l1CategoryAsc', label: 'L1-kategori (A-O)'),
   ];
 
   @override
@@ -32,6 +33,17 @@ class InventoryScreen extends ConsumerWidget {
         onRetry: () => ref.invalidate(inventoryProvider),
       ),
       data: (items) {
+        final visibleItems = [...items];
+        if (sort == 'l1CategoryAsc') {
+          visibleItems.sort((a, b) {
+            final byCategory = a.l1Category.toLowerCase().compareTo(
+              b.l1Category.toLowerCase(),
+            );
+            if (byCategory != 0) return byCategory;
+            return a.displayName.toLowerCase().compareTo(b.displayName.toLowerCase());
+          });
+        }
+
         final filterSection = Padding(
           padding: const EdgeInsets.fromLTRB(12, 12, 12, 4),
           child: Column(
@@ -83,7 +95,7 @@ class InventoryScreen extends ConsumerWidget {
           ),
         );
 
-        if (items.isEmpty) {
+        if (visibleItems.isEmpty) {
           return Stack(
             children: [
               ListView(
@@ -109,11 +121,11 @@ class InventoryScreen extends ConsumerWidget {
           children: [
             ListView.separated(
               padding: const EdgeInsets.only(bottom: 88),
-              itemCount: items.length + 1,
+              itemCount: visibleItems.length + 1,
               separatorBuilder: (_, __) => const Divider(height: 1),
               itemBuilder: (context, index) {
                 if (index == 0) return filterSection;
-                final item = items[index - 1];
+                final item = visibleItems[index - 1];
                 return SwipeableInventoryTile(item: item);
               },
             ),