Add tender card shimmer loading

lib/views/tenders/widgets/recommended_tenders_view.dart

@@ -6,6 +6,7 @@ import 'package:tm_app/view_models/ai_recommendations_view_model.dart';
 
 import '../strings/tenders_strings.dart';
 import 'main_tenders_slider.dart';
+import 'tender_card_shimmer.dart';
 
 /// The "Recommended" tab body. Handles loading, empty/"still learning",
 /// error+retry and the recommended tender list for [AiRecommendationsViewModel].
@@ -34,7 +35,7 @@ class _RecommendedTendersViewState extends State<RecommendedTendersView> {
     return Consumer<AiRecommendationsViewModel>(
       builder: (context, vm, child) {
         if (vm.isLoading) {
-          return const _LoadingSkeleton();
+          return _LoadingSkeleton(isDesktop: widget.isDesktop);
         }
         if (vm.errorMessage != null) {
           return _MessageState(
@@ -152,23 +153,18 @@ class _MessageState extends StatelessWidget {
 
 /// Simple placeholder list shown while recommendations load.
 class _LoadingSkeleton extends StatelessWidget {
-  const _LoadingSkeleton();
+  const _LoadingSkeleton({required this.isDesktop});
+
+  final bool isDesktop;
 
   @override
   Widget build(BuildContext context) {
     return ListView.separated(
       padding: EdgeInsets.all(16.0.h()),
-      itemCount: 4,
-      separatorBuilder: (_, __) => SizedBox(height: 12.0.h()),
-      itemBuilder:
-          (context, index) => Container(
-            height: 120.0.h(),
-            decoration: BoxDecoration(
-              color: AppColors.grey0,
-              borderRadius: BorderRadius.circular(12.0.w()),
-              border: Border.all(color: AppColors.grey30),
-            ),
-          ),
+      itemCount: isDesktop ? 3 : 2,
+      separatorBuilder:
+          (_, __) => SizedBox(height: isDesktop ? 20.0.h() : 52.0.h()),
+      itemBuilder: (context, index) => TenderCardShimmer(isDesktop: isDesktop),
     );
   }
 }