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

flutter/lib/core/ui/category_then_product_picker.dart

@@ -64,28 +64,19 @@ 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
-      if (!context.mounted) return null;
-      selectedCategory = await showModalBottomSheet<AdminCategoryNode>(
-        context: context,
-        isScrollControlled: true,
-        useSafeArea: true,
-        builder: (ctx) => _CategoryPickerSheet(
-          tree: categoryTree,
-          preselectedId: preselectedCategoryId,
-          onSelected: (node) => Navigator.pop(ctx, node),
-        ),
-      );
-      if (selectedCategory == null || !context.mounted) return null;
-    }
+    // Steg 1 — visa alltid kategoriträd (med eventuell förmarkering)
+    if (!context.mounted) return null;
+    final selectedCategory = await showModalBottomSheet<AdminCategoryNode>(
+      context: context,
+      isScrollControlled: true,
+      useSafeArea: true,
+      builder: (ctx) => _CategoryPickerSheet(
+        tree: categoryTree,
+        preselectedId: preselectedCategoryId,
+        onSelected: (node) => Navigator.pop(ctx, node),
+      ),
+    );
+    if (selectedCategory == null || !context.mounted) return null;
 
     // Samla alla kategori-IDs i den valda grenen (inkl. ättlingar)
     final categoryIds = _collectIds(selectedCategory);
@@ -98,8 +89,8 @@ class CategoryThenProductPicker {
 
     // Bygg eventuell onCreate-callback med categoryId inbunden
     final onCreateBound = onCreate == null
-        ? null
-        : (String name) => onCreate(name, selectedCategory!.id);
+      ? null
+      : (String name) => onCreate(name, selectedCategory.id);
 
     // Steg 2 — välj produkt
     if (!context.mounted) return null;