improve asnyc loading and error widgets

app/lib/features/bangs/presentation/screens/search.dart

@@ -99,7 +99,7 @@ class BangSearchScreen extends HookConsumerWidget {
         error: (error, stackTrace) => Center(
           child: FailureWidget(title: 'Bang Search failed', exception: error),
         ),
-        loading: () => const SizedBox.shrink(),
+        loading: () => const Center(child: CircularProgressIndicator()),
       ),
     );
   }

app/lib/features/geckoview/features/bookmarks/presentation/screens/bookmark_list.dart

@@ -362,7 +362,7 @@ class BookmarkListScreen extends HookConsumerWidget {
                 },
               ),
             ),
-            loading: () => const SizedBox.shrink(),
+            loading: () => const Center(child: CircularProgressIndicator()),
           ),
         ),
       ),

app/lib/features/geckoview/features/bookmarks/presentation/widgets/folder_tree_picker.dart

@@ -156,7 +156,7 @@ class FolderTreePicker extends HookConsumerWidget {
               },
             ),
           ),
-          loading: () => const SizedBox.shrink(),
+          loading: () => const Center(child: CircularProgressIndicator()),
         ),
       ],
     );

app/lib/features/geckoview/features/browser/presentation/widgets/sheets/tracking_protection_section.dart

@@ -52,7 +52,14 @@ class TrackingProtectionSection extends HookConsumerWidget {
           secondary: const Icon(Icons.shield_outlined),
         ),
       ),
-      error: (error, stack) => const SizedBox.shrink(),
+      error: (error, stack) {
+        final colorScheme = Theme.of(context).colorScheme;
+
+        return ListTile(
+          title: const Text('Failed to load tracking protection'),
+          leading: Icon(Icons.error_outline, color: colorScheme.error),
+        );
+      },
     );
   }
 }

app/lib/features/geckoview/features/readerview/presentation/widgets/reader_button.dart

@@ -75,7 +75,8 @@ class ReaderButton extends HookConsumerWidget {
           readerabilityState.active,
           icon,
         ),
-        error: (error, stackTrace) => SizedBox.shrink(),
+        error: (error, stackTrace) =>
+            Center(child: Icon(Icons.error_outline, color: colorScheme.error)),
         loading: () => AnimateGradientShader(
           duration: const Duration(milliseconds: 500),
           primaryEnd: Alignment.bottomLeft,

app/lib/features/geckoview/features/tabs/presentation/screens/container_list.dart

@@ -32,6 +32,7 @@ import 'package:weblibre/features/geckoview/features/tabs/domain/providers/selec
 import 'package:weblibre/features/geckoview/features/tabs/domain/repositories/container.dart';
 import 'package:weblibre/features/geckoview/features/tabs/presentation/widgets/container_list_tile.dart';
 import 'package:weblibre/features/tor/presentation/controllers/start_tor_proxy.dart';
+import 'package:weblibre/presentation/widgets/failure_widget.dart';
 
 class ContainerListScreen extends HookConsumerWidget {
   const ContainerListScreen();
@@ -136,7 +137,13 @@ class ContainerListScreen extends HookConsumerWidget {
               );
             },
           ),
-          error: (error, stackTrace) => SizedBox.shrink(),
+          error: (error, stackTrace) => Center(
+            child: FailureWidget(
+              title: 'Failed to load containers',
+              exception: error,
+              onRetry: () => ref.invalidate(watchContainersWithCountProvider),
+            ),
+          ),
           loading: () => ListView.builder(
             itemCount: 3,
             itemBuilder: (context, index) => ContainerListTile(

app/lib/features/geckoview/features/tabs/presentation/screens/container_selection.dart

@@ -30,6 +30,7 @@ import 'package:weblibre/features/geckoview/features/tabs/data/models/container_
 import 'package:weblibre/features/geckoview/features/tabs/domain/providers.dart';
 import 'package:weblibre/features/geckoview/features/tabs/domain/repositories/container.dart';
 import 'package:weblibre/features/geckoview/features/tabs/presentation/widgets/container_list_tile.dart';
+import 'package:weblibre/presentation/widgets/failure_widget.dart';
 
 class ContainerSelectionScreen extends HookConsumerWidget {
   const ContainerSelectionScreen();
@@ -62,7 +63,13 @@ class ContainerSelectionScreen extends HookConsumerWidget {
               );
             },
           ),
-          error: (error, stackTrace) => SizedBox.shrink(),
+          error: (error, stackTrace) => Center(
+            child: FailureWidget(
+              title: 'Failed to load containers',
+              exception: error,
+              onRetry: () => ref.invalidate(watchContainersWithCountProvider),
+            ),
+          ),
           loading: () => ListView.builder(
             itemCount: 3,
             itemBuilder: (context, index) => ContainerListTile(

app/lib/features/geckoview/features/tabs/presentation/widgets/container_chips.dart

@@ -256,7 +256,17 @@ class ContainerChips extends HookConsumerWidget {
           ),
         );
       },
-      error: (error, stackTrace) => const SizedBox.shrink(),
+      error: (error, stackTrace) => SizedBox(
+        height: 48,
+        width: double.infinity,
+        child: Center(
+          child: Icon(
+            Icons.error_outline,
+            size: 20,
+            color: Theme.of(context).colorScheme.error,
+          ),
+        ),
+      ),
       loading: () => const SizedBox(height: 48, width: double.infinity),
     );
   }

app/lib/features/onboarding/presentation/pages/default_search.dart

@@ -29,6 +29,7 @@ import 'package:weblibre/features/settings/presentation/controllers/save_setting
 import 'package:weblibre/features/settings/presentation/widgets/bang_icon.dart';
 import 'package:weblibre/features/user/data/models/general_settings.dart';
 import 'package:weblibre/features/user/domain/repositories/general_settings.dart';
+import 'package:weblibre/presentation/widgets/failure_widget.dart';
 import 'package:weblibre/presentation/widgets/url_icon.dart';
 
 const defaultBangs = ['ddg', 'brave', 'startpage', 'qwant'];
@@ -161,7 +162,14 @@ class DefaultSearchPage extends HookConsumerWidget {
             ],
           );
         },
-        error: (error, stackTrace) => const SizedBox.shrink(),
+        error: (error, stackTrace) => Center(
+          child: FailureWidget(
+            title: 'Could not load search engines',
+            exception: error,
+            onRetry: () =>
+                ref.refresh(bangListProvider(triggers: defaultBangs)),
+          ),
+        ),
         loading: () => const SizedBox(height: 48, width: double.infinity),
       ),
     );

app/lib/features/settings/presentation/screens/web_engine_hardening.dart

@@ -129,7 +129,7 @@ class WebEngineHardeningScreen extends HookConsumerWidget {
             ),
           ),
         ),
-        loading: () => const SizedBox.shrink(),
+        loading: () => const Center(child: CircularProgressIndicator()),
       ),
     );
   }

app/lib/features/settings/presentation/screens/web_engine_hardening_group.dart

@@ -198,7 +198,7 @@ class WebEngineHardeningGroupScreen extends HookConsumerWidget {
             ),
           ),
         ),
-        loading: () => const SizedBox.shrink(),
+        loading: () => const Center(child: CircularProgressIndicator()),
       ),
     );
   }

app/lib/features/settings/presentation/widgets/default_search_selector.dart

@@ -83,7 +83,9 @@ class DefaultSearchSelector extends HookConsumerWidget {
           ),
         );
       },
-      error: (error, stackTrace) => const SizedBox.shrink(),
+      error: (error, stackTrace) => Center(
+        child: Icon(Icons.error, color: Theme.of(context).colorScheme.error),
+      ),
       loading: () => const SizedBox(height: 48, width: double.infinity),
     );
   }

app/lib/features/web_feed/presentation/screens/feed_article_list.dart

@@ -190,7 +190,7 @@ class FeedArticleListScreen extends HookConsumerWidget {
               exception: error,
             ),
           ),
-          loading: () => const SizedBox.shrink(),
+          loading: () => const Center(child: CircularProgressIndicator()),
         ),
       ),
     );

app/lib/features/web_feed/presentation/screens/feed_list.dart

@@ -93,7 +93,7 @@ class FeedListScreen extends HookConsumerWidget {
             },
           ),
         ),
-        loading: () => const SizedBox.shrink(),
+        loading: () => const Center(child: CircularProgressIndicator()),
       ),
       floatingActionButton: FloatingActionButton.extended(
         label: const Text('Feed'),

app/lib/features/web_feed/presentation/widgets/feed_card.dart

@@ -146,7 +146,13 @@ class FeedCard extends HookConsumerWidget {
                           );
                         },
                         error: (error, stackTrace) => const Text('N/A'),
-                        loading: () => const SizedBox.shrink(),
+                        loading: () => const SizedBox(
+                          height: 16,
+                          width: 16,
+                          child: Center(
+                            child: CircularProgressIndicator(strokeWidth: 2),
+                          ),
+                        ),
                       );
                     },
                   ),