feat: implement grid layout for recipes with column selection and improve pantry product picker

Co-authored-by: Copilot <copilot@github.com>

flutter/lib/core/ui/app_shell.dart

@@ -3,6 +3,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../features/auth/data/auth_providers.dart';
+import '../../features/recipes/data/recipes_grid_provider.dart';
 
 const _adminDestination = _AppDestination(
   path: '/admin',
@@ -94,10 +95,26 @@ class AppShell extends ConsumerWidget {
       }
     }
 
+    final isRecipesRoute = location.startsWith('/recipes') &&
+        !location.startsWith('/recipes/');
+
     return Scaffold(
       appBar: AppBar(
         title: Text(selectedDestination.title),
         actions: [
+          if (isRecipesRoute)
+            PopupMenuButton<int>(
+              icon: const Icon(Icons.grid_view),
+              tooltip: 'Välj antal kolumner',
+              onSelected: (columns) =>
+                  ref.read(recipesGridProvider.notifier).setColumns(columns),
+              itemBuilder: (context) => const [
+                PopupMenuItem(value: 2, child: Text('2 kolumner')),
+                PopupMenuItem(value: 4, child: Text('4 kolumner')),
+                PopupMenuItem(value: 6, child: Text('6 kolumner')),
+                PopupMenuItem(value: 8, child: Text('8 kolumner')),
+              ],
+            ),
           IconButton(
             tooltip: 'Logga ut',
             icon: const Icon(Icons.logout),