refactor(category-picker): streamline category selection flow in product picker

flutter/lib/core/ui/category_then_product_picker.dart

@@ -64,17 +64,9 @@ class CategoryThenProductPicker {
     String? initialQuery,
     Future<ProductOption?> Function(String name, int categoryId)? onCreate,
   }) async {
-    AdminCategoryNode? selectedCategory;
-
-    if (preselectedCategoryId != null) {
-      // AI-föreslagen kategori — hoppa direkt till produktpickern
-      selectedCategory = _findNode(categoryTree, preselectedCategoryId);
-    }
-
-    if (selectedCategory == null) {
-      // Steg 1 — visa kategoriträd
+    // Steg 1 — visa alltid kategoriträd (med eventuell förmarkering)
     if (!context.mounted) return null;
-      selectedCategory = await showModalBottomSheet<AdminCategoryNode>(
+    final selectedCategory = await showModalBottomSheet<AdminCategoryNode>(
       context: context,
       isScrollControlled: true,
       useSafeArea: true,
@@ -85,7 +77,6 @@ class CategoryThenProductPicker {
       ),
     );
     if (selectedCategory == null || !context.mounted) return null;
-    }
 
     // Samla alla kategori-IDs i den valda grenen (inkl. ättlingar)
     final categoryIds = _collectIds(selectedCategory);
@@ -99,7 +90,7 @@ class CategoryThenProductPicker {
     // Bygg eventuell onCreate-callback med categoryId inbunden
     final onCreateBound = onCreate == null
       ? null
-        : (String name) => onCreate(name, selectedCategory!.id);
+      : (String name) => onCreate(name, selectedCategory.id);
 
     // Steg 2 — välj produkt
     if (!context.mounted) return null;