app/lib/features/catalog/data/supabase_catalog_repository.dart

@@ -101,13 +101,16 @@ class SupabaseCatalogRepository implements CatalogRepository {
     }
   }
 
-  /// Maps and logs an error. Logs the failure kind and the error type only.
+  /// Maps and logs an error. Logs the failure kind only.
   CatalogFailure _fail(String operation, Object error) {
     final failure = mapCatalogError(error);
-    _log.warning(
-      'Catalog $operation failed: ${failure.runtimeType} '
-      '(${error.runtimeType})',
-    );
+    // Stable names (runtime type names are minified on the web).
+    final kind = switch (failure) {
+      CatalogNetworkFailure() => 'network',
+      CatalogInvalidInputFailure() => 'invalidInput',
+      CatalogUnexpectedFailure() => 'unexpected',
+    };
+    _log.warning('Catalog $operation failed: $kind');
     return failure;
   }
 }

app/lib/features/catalog/presentation/search/catalog_search_view.dart

@@ -263,37 +263,52 @@ class _CatalogSearchViewState extends ConsumerState<CatalogSearchView> {
             child: Column(
               crossAxisAlignment: CrossAxisAlignment.stretch,
               children: [
-                Padding(
-                  padding: EdgeInsets.fromLTRB(
-                    padding.left,
-                    padding.top,
-                    padding.right,
-                    AppSpacing.sm,
+                FocusTraversalOrder(
+                  order: const NumericFocusOrder(1),
+                  child: Padding(
+                    padding: EdgeInsets.fromLTRB(
+                      padding.left,
+                      padding.top,
+                      padding.right,
+                      AppSpacing.sm,
+                    ),
+                    child: _buildHeader(state, showFilterButton: !expanded),
+                  ),
+                ),
+                Expanded(
+                  child: FocusTraversalOrder(
+                    order: const NumericFocusOrder(3),
+                    child: _buildResults(state, padding),
                   ),
-                  child: _buildHeader(state, showFilterButton: !expanded),
                 ),
-                Expanded(child: _buildResults(state, padding)),
               ],
             ),
           ),
         );
-        if (!expanded) {
-          return main;
-        }
-        return Row(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            SizedBox(
-              width: _sidebarWidth,
-              child: SingleChildScrollView(
-                key: const Key('catalog_filter_sidebar'),
-                padding: EdgeInsets.all(padding.left),
-                child: _buildSidebar(state),
-              ),
-            ),
-            const VerticalDivider(width: 1),
-            Expanded(child: main),
-          ],
+        // Tab order (Spec #3 § 6): search field, filters, list. With the side
+        // bar left of the field the visual order alone would be wrong.
+        return FocusTraversalGroup(
+          policy: OrderedTraversalPolicy(),
+          child: expanded
+              ? Row(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    FocusTraversalOrder(
+                      order: const NumericFocusOrder(2),
+                      child: SizedBox(
+                        width: _sidebarWidth,
+                        child: SingleChildScrollView(
+                          key: const Key('catalog_filter_sidebar'),
+                          padding: EdgeInsets.all(padding.left),
+                          child: _buildSidebar(state),
+                        ),
+                      ),
+                    ),
+                    const VerticalDivider(width: 1),
+                    Expanded(child: main),
+                  ],
+                )
+              : main,
         );
       },
     );

app/lib/features/catalog/presentation/search/widgets/catalog_filter_panel.dart

@@ -118,24 +118,29 @@ class _SingleChoice extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    // A controlled drop-down (no form field that keeps its own value), so a
+    // selection does not rebuild the field and keyboard focus stays on it.
     return KeyedSubtree(
       key: fieldKey,
-      child: DropdownButtonFormField<int?>(
-        key: ValueKey(value),
-        // The field keeps its own value; a new key follows outside changes
-        // (reset, URL).
-        initialValue: value,
-        isExpanded: true,
+      child: InputDecorator(
+        // "Any" is a value too, so the label always floats.
+        isEmpty: false,
         decoration: InputDecoration(labelText: label),
-        items: [
-          DropdownMenuItem<int?>(child: Text(anyLabel)),
-          for (final option in options)
-            DropdownMenuItem<int?>(
-              value: option,
-              child: Text(optionLabel(option)),
-            ),
-        ],
-        onChanged: onChanged,
+        child: DropdownButtonHideUnderline(
+          child: DropdownButton<int?>(
+            value: value,
+            isExpanded: true,
+            items: [
+              DropdownMenuItem<int?>(child: Text(anyLabel)),
+              for (final option in options)
+                DropdownMenuItem<int?>(
+                  value: option,
+                  child: Text(optionLabel(option)),
+                ),
+            ],
+            onChanged: onChanged,
+          ),
+        ),
       ),
     );
   }

app/lib/features/catalog/presentation/search/widgets/catalog_game_tile.dart

@@ -8,9 +8,10 @@ import 'package:shuffle/features/catalog/domain/catalog_game_summary.dart';
 ///
 /// Shows a [GameCover] placeholder (no image URL in #3), title, year,
 /// publishers and short facts; missing facts are left out. [onTap] is `null`
-/// in #3: the tile is then not a button (no dead link) but still focusable
-/// programmatically ([focusNode]) so keyboard focus can move to the first
-/// newly loaded tile.
+/// in #3: the tile is then not a button (no dead link) but stays a keyboard
+/// stop with a visible focus ring, so keyboard users can walk the list (which
+/// scrolls it and loads more) and focus can move to the first newly loaded
+/// tile ([focusNode]).
 class CatalogGameTile extends StatefulWidget {
   const CatalogGameTile({
     required this.game,
@@ -147,8 +148,6 @@ class _CatalogGameTileState extends State<CatalogGameTile> {
     final onTap = widget.onTap;
     return Focus(
       focusNode: widget.focusNode,
-      // Not a tab stop while the tile does nothing, but focusable by code.
-      skipTraversal: onTap == null,
       onFocusChange: (focused) => setState(() => _focused = focused),
       child: Semantics(
         container: true,

app/test/features/catalog/presentation/search/catalog_search_a11y_test.dart

@@ -3,7 +3,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:shuffle/features/catalog/domain/catalog_search_query.dart';
 
 import '../../catalog_test_support.dart';
-import 'catalog_search_view_test.dart';
+import 'catalog_search_test_support.dart';
 
 void main() {
   group('announcements', () {

app/test/features/catalog/presentation/search/catalog_search_behavior_test.dart

@@ -5,7 +5,7 @@ import 'package:shuffle/features/catalog/domain/catalog_failure.dart';
 import 'package:shuffle/features/catalog/domain/catalog_search_query.dart';
 
 import '../../catalog_test_support.dart';
-import 'catalog_search_view_test.dart';
+import 'catalog_search_test_support.dart';
 
 Future<void> openFilterSheet(WidgetTester tester) async {
   await tester.tap(find.byKey(const Key('catalog_filter_button')));
@@ -184,25 +184,128 @@ void main() {
   });
 
   group('keyboard', () {
-    testWidgets('QUE-06 Kriterium 4: Tab leads from the field to the filters', (
+    Future<void> tab(WidgetTester tester) async {
+      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
+      await tester.pump();
+    }
+
+    bool focusIsIn(Finder finder) {
+      final focused = FocusManager.instance.primaryFocus?.context;
+      return focused != null &&
+          find
+              .descendant(
+                of: finder,
+                matching: find.byElementPredicate((e) => e == focused),
+              )
+              .evaluate()
+              .isNotEmpty;
+    }
+
+    /// The tile's `Focus` sits above its keyed card.
+    bool focusOnTile(String id) {
+      final focused = FocusManager.instance.primaryFocus?.context;
+      return focused != null &&
+          find
+              .ancestor(
+                of: find.byKey(Key('catalog_tile_$id')),
+                matching: find.byElementPredicate((e) => e == focused),
+              )
+              .evaluate()
+              .isNotEmpty;
+    }
+
+    double scrollOffset(WidgetTester tester) => tester
+        .state<ScrollableState>(
+          find.descendant(
+            of: find.byKey(const Key('catalog_result_list')),
+            matching: find.byType(Scrollable),
+          ),
+        )
+        .position
+        .pixels;
+
+    testWidgets(
+      'QUE-06 Kriterium 4: Tab walks field, filters, list (compact)',
+      (tester) async {
+        final repository = FakeCatalogRepository(all: List.generate(75, game));
+        await pumpView(tester, repository);
+
+        await tester.tap(searchInput);
+        await tester.pump();
+        await tab(tester);
+        expect(
+          focusIsIn(find.byKey(const Key('catalog_filter_button'))),
+          isTrue,
+        );
+
+        await tab(tester);
+        expect(focusOnTile('game-0'), isTrue);
+
+        // Walking on scrolls the list (and so loads more).
+        for (var i = 0; i < 12; i++) {
+          await tab(tester);
+        }
+        expect(scrollOffset(tester), greaterThan(0));
+        expect(focusOnTile('game-12'), isTrue);
+      },
+    );
+
+    testWidgets(
+      'QUE-06 Kriterium 4: Tab order is field, filters, list (side bar)',
+      (tester) async {
+        final repository = FakeCatalogRepository(all: List.generate(75, game));
+        await pumpView(tester, repository, width: 1200);
+
+        await tester.tap(searchInput);
+        await tester.pump();
+        await tab(tester);
+        expect(
+          focusIsIn(find.byKey(const Key('catalog_filter_sidebar'))),
+          isTrue,
+          reason: 'the filters come right after the search field',
+        );
+
+        // Through the filters (3 selects, 2 chip groups, reset) to the list.
+        var steps = 0;
+        while (!focusOnTile('game-0') && steps++ < 30) {
+          await tab(tester);
+        }
+        expect(focusOnTile('game-0'), isTrue);
+        expect(steps, lessThan(30));
+      },
+    );
+
+    testWidgets('a selection keeps keyboard focus on the select', (
       tester,
     ) async {
       final repository = FakeCatalogRepository(all: [game(1)]);
       await pumpView(tester, repository);
+      await openFilterSheet(tester);
 
-      await tester.tap(searchInput);
-      await tester.pump();
-      await tester.sendKeyEvent(LogicalKeyboardKey.tab);
-      await tester.pump();
-      final focused = FocusManager.instance.primaryFocus!.context;
+      await tester.tap(find.byKey(const Key('catalog_filter_players')));
+      await tester.pumpAndSettle();
+      await tester.tap(find.text('4 Spieler').last);
+      await tester.pumpAndSettle();
+
+      expect(repository.calls.last.query.filters.players, 4);
       expect(
-        find.descendant(
-          of: find.byKey(const Key('catalog_filter_button')),
-          matching: find.byElementPredicate((e) => e == focused),
-        ),
-        findsOneWidget,
+        focusIsIn(find.byKey(const Key('catalog_filter_players'))),
+        isTrue,
       );
     });
+
+    testWidgets('the sheet stays open while filters change the URL state', (
+      tester,
+    ) async {
+      final repository = FakeCatalogRepository(all: [game(1)]);
+      await pumpView(tester, repository);
+      await openFilterSheet(tester);
+
+      await tester.tap(find.byKey(const Key('catalog_term_$genreFamily')));
+      await tester.pumpAndSettle();
+
+      expect(find.byKey(const Key('catalog_filter_sheet')), findsOneWidget);
+    });
   });
 
   group('layout', () {

app/test/features/catalog/presentation/search/catalog_search_screen_test.dart

@@ -13,7 +13,7 @@ import 'package:shuffle/features/catalog/presentation/search/catalog_search_view
 import '../../../../helpers/pump_app.dart';
 import '../../../../helpers/router_helpers.dart';
 import '../../catalog_test_support.dart';
-import 'catalog_search_view_test.dart';
+import 'catalog_search_test_support.dart';
 
 void main() {
   group('route /catalog', () {
@@ -187,6 +187,8 @@ void main() {
       final params = currentUri(router).queryParameters;
       expect(params['q'], 'alt');
       expect(params['genre'], genreFamily);
+      // Writing the URL does not close the open filter sheet.
+      expect(find.byKey(const Key('catalog_filter_sheet')), findsOneWidget);
     });
 
     testWidgets('outside the web nothing is written', (tester) async {

app/test/features/catalog/presentation/search/catalog_search_test_support.dart

@@ -0,0 +1,48 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shuffle/features/catalog/domain/catalog_search_query.dart';
+import 'package:shuffle/features/catalog/presentation/search/catalog_search_view.dart';
+
+import '../../../../helpers/pump_app.dart';
+import '../../catalog_test_support.dart';
+
+/// Sets a logical window size for the test (device pixel ratio 1).
+void useWindow(WidgetTester tester, double width, [double height = 900]) {
+  tester.view.physicalSize = Size(width, height);
+  tester.view.devicePixelRatio = 1;
+  addTearDown(tester.view.reset);
+}
+
+Future<void> pumpView(
+  WidgetTester tester,
+  FakeCatalogRepository repository, {
+  CatalogSearchQuery initialQuery = const CatalogSearchQuery(),
+  ValueChanged<String>? onReportGame,
+  Locale locale = const Locale('de'),
+  double? textScale,
+  double width = 420,
+  bool settle = true,
+}) async {
+  useWindow(tester, width);
+  await pumpApp(
+    tester,
+    locale: locale,
+    textScale: textScale,
+    overrides: catalogOverrides(repository),
+    settle: false,
+    home: Scaffold(
+      body: CatalogSearchView(
+        initialQuery: initialQuery,
+        onReportGame: onReportGame,
+      ),
+    ),
+  );
+  if (settle) {
+    await tester.pumpAndSettle();
+  }
+}
+
+Finder get searchInput => find.descendant(
+  of: find.byKey(const Key('catalog_search_field')),
+  matching: find.byType(TextField),
+);

app/test/features/catalog/presentation/search/catalog_search_view_test.dart

@@ -4,51 +4,9 @@ import 'package:shuffle/core/widgets/game_cover.dart';
 import 'package:shuffle/features/catalog/domain/catalog_failure.dart';
 import 'package:shuffle/features/catalog/domain/catalog_search_query.dart';
 import 'package:shuffle/features/catalog/presentation/search/catalog_search_controller.dart';
-import 'package:shuffle/features/catalog/presentation/search/catalog_search_view.dart';
 
-import '../../../../helpers/pump_app.dart';
 import '../../catalog_test_support.dart';
-
-/// Sets a logical window size for the test (device pixel ratio 1).
-void useWindow(WidgetTester tester, double width, [double height = 900]) {
-  tester.view.physicalSize = Size(width, height);
-  tester.view.devicePixelRatio = 1;
-  addTearDown(tester.view.reset);
-}
-
-Future<void> pumpView(
-  WidgetTester tester,
-  FakeCatalogRepository repository, {
-  CatalogSearchQuery initialQuery = const CatalogSearchQuery(),
-  ValueChanged<String>? onReportGame,
-  Locale locale = const Locale('de'),
-  double? textScale,
-  double width = 420,
-  bool settle = true,
-}) async {
-  useWindow(tester, width);
-  await pumpApp(
-    tester,
-    locale: locale,
-    textScale: textScale,
-    overrides: catalogOverrides(repository),
-    settle: false,
-    home: Scaffold(
-      body: CatalogSearchView(
-        initialQuery: initialQuery,
-        onReportGame: onReportGame,
-      ),
-    ),
-  );
-  if (settle) {
-    await tester.pumpAndSettle();
-  }
-}
-
-Finder get searchInput => find.descendant(
-  of: find.byKey(const Key('catalog_search_field')),
-  matching: find.byType(TextField),
-);
+import 'catalog_search_test_support.dart';
 
 void main() {
   group('list and tiles', () {