feat: enhance EmptyStateView layout with positioned action button for better UX

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

@@ -21,13 +21,19 @@ class InventoryScreen extends ConsumerWidget {
       ),
       data: (items) {
         if (items.isEmpty) {
-          return EmptyStateView(
-            title: 'Inventariet är tomt.',
-            action: FloatingActionButton.extended(
-              onPressed: () => context.push('/inventory/create'),
-              icon: const Icon(Icons.add),
-              label: const Text('Lägg till'),
-            ),
+          return Stack(
+            children: [
+              const EmptyStateView(title: 'Inventariet är tomt.'),
+              Positioned(
+                right: 16,
+                bottom: 16,
+                child: FloatingActionButton.extended(
+                  onPressed: () => context.push('/inventory/create'),
+                  icon: const Icon(Icons.add),
+                  label: const Text('Lägg till'),
+                ),
+              ),
+            ],
           );
         }
         return Stack(