feat: Add location display and category chips in pantry and inventory screens

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

@@ -218,6 +218,13 @@ class _InventoryEditScreenState extends ConsumerState<InventoryEditScreen> {
   }
 
   Future<void> _save() async {
+    if (_selectedProductId == null) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.inventorySelectProduct)),
+      );
+      return;
+    }
+
     if (!_formKey.currentState!.validate()) return;
     setState(() => _saving = true);
     try {

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

@@ -286,10 +286,12 @@ class _ForegroundTile extends ConsumerWidget {
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final theme = Theme.of(context);
+    final location = item.location?.trim();
+    final hasLocation = location != null && location.isNotEmpty;
 
     final subtitleText = [
       '${_fmtQty(item.quantity)} ${item.unit}',
-      if (item.location != null && item.location!.isNotEmpty) item.location!,
+      if (hasLocation) location,
       if (item.bestBeforeDate != null)
         'Bäst före: ${_formatDate(item.bestBeforeDate!)}',
     ].join(' · ');
@@ -305,22 +307,50 @@ class _ForegroundTile extends ConsumerWidget {
               )
             : null,
         title: Text(item.displayName),
-        // Subtitle: small swipe-hint icon + text on the same row.
-        subtitle: Row(
+        // Subtitle: swipe hint + details on first line, category chip below.
+        subtitle: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          mainAxisSize: MainAxisSize.min,
           children: [
-            if (!selectableMode) ...[
-              Icon(
-                Icons.swap_horiz,
-                size: 13,
-                color: theme.colorScheme.outline,
-              ),
-              const SizedBox(width: 3),
-            ],
-            Expanded(
-              child: Text(
-                subtitleText,
-                overflow: TextOverflow.ellipsis,
-              ),
+            Row(
+              children: [
+                if (!selectableMode) ...[
+                  Icon(
+                    Icons.swap_horiz,
+                    size: 13,
+                    color: theme.colorScheme.outline,
+                  ),
+                  const SizedBox(width: 3),
+                ],
+                Expanded(
+                  child: Text(
+                    subtitleText,
+                    overflow: TextOverflow.ellipsis,
+                  ),
+                ),
+              ],
+            ),
+            const SizedBox(height: 6),
+            Row(
+              children: [
+                Flexible(
+                  child: Chip(
+                    label: Text(
+                      'L1: ${item.l1Category}',
+                      maxLines: 1,
+                      overflow: TextOverflow.ellipsis,
+                    ),
+                    padding: EdgeInsets.zero,
+                    visualDensity: VisualDensity.compact,
+                    materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
+                    side: BorderSide(color: theme.colorScheme.outlineVariant),
+                    backgroundColor: theme.colorScheme.surface,
+                    labelStyle: theme.textTheme.bodySmall?.copyWith(
+                      color: theme.colorScheme.onSurfaceVariant,
+                    ),
+                  ),
+                ),
+              ],
             ),
           ],
         ),