fix(ui): improve adaptive phone and tablet layouts

test/adaptive_layout_test.dart

@@ -0,0 +1,87 @@
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:spotiflac_android/utils/adaptive_layout.dart';
+
+void main() {
+  group('adaptive navigation', () {
+    test('keeps phone and tablet widths on reachable bottom navigation', () {
+      expect(useNavigationRailForWidth(390), isFalse);
+      expect(useNavigationRailForWidth(1032), isFalse);
+      expect(useNavigationRailForWidth(1366), isFalse);
+    });
+
+    test('reserves the navigation rail for desktop-width windows', () {
+      expect(useNavigationRailForWidth(navigationRailBreakpoint - 1), isFalse);
+      expect(useNavigationRailForWidth(navigationRailBreakpoint), isTrue);
+    });
+  });
+
+  group('wide content', () {
+    test('uses the full tablet width before applying a small gutter', () {
+      expect(wideInsetForWidth(853), 0);
+      expect(wideInsetForWidth(1024), 32);
+      expect(wideInsetForWidth(1366), maxWideContentInset);
+    });
+
+    test('never removes more than the shared gutter from each side', () {
+      expect(adaptiveContentMaxWidth(1366), 1302);
+    });
+  });
+
+  group('adaptive UI scale', () {
+    test('keeps phone density unchanged', () {
+      expect(adaptiveUiScaleForSize(const Size(430, 932)), 1);
+    });
+
+    test('enlarges compact and large tablet touch surfaces', () {
+      expect(adaptiveUiScaleForSize(const Size(700, 1000)), 1.1);
+      expect(adaptiveUiScaleForSize(const Size(1024, 1366)), 1.2);
+      expect(adaptiveUiScaleForSize(const Size(1366, 1024)), 1.2);
+    });
+
+    test('keeps desktop-width windows at native density', () {
+      expect(adaptiveUiScaleForSize(const Size(1440, 900)), 1);
+    });
+
+    testWidgets('reflows the tablet viewport and preserves touch mapping', (
+      tester,
+    ) async {
+      tester.view.physicalSize = const Size(2048, 2732);
+      tester.view.devicePixelRatio = 2;
+      addTearDown(tester.view.resetPhysicalSize);
+      addTearDown(tester.view.resetDevicePixelRatio);
+
+      Size? innerSize;
+      var taps = 0;
+      await tester.pumpWidget(
+        MediaQuery(
+          data: MediaQueryData.fromView(tester.view),
+          child: Directionality(
+            textDirection: TextDirection.ltr,
+            child: AdaptiveUiScaler(
+              child: Builder(
+                builder: (context) {
+                  innerSize = MediaQuery.sizeOf(context);
+                  return Align(
+                    alignment: Alignment.topLeft,
+                    child: GestureDetector(
+                      behavior: HitTestBehavior.opaque,
+                      onTap: () => taps++,
+                      child: const SizedBox.square(dimension: 100),
+                    ),
+                  );
+                },
+              ),
+            ),
+          ),
+        ),
+      );
+
+      expect(innerSize!.width, closeTo(1024 / 1.2, 0.01));
+      expect(innerSize!.height, closeTo(1366 / 1.2, 0.01));
+      await tester.tapAt(const Offset(110, 110));
+      await tester.pump();
+      expect(taps, 1);
+    });
+  });
+}

test/design_system_test.dart

@@ -12,6 +12,7 @@ import 'package:spotiflac_android/theme/app_theme.dart';
 import 'package:spotiflac_android/theme/app_tokens.dart';
 import 'package:spotiflac_android/theme/cover_palette.dart';
 import 'package:spotiflac_android/widgets/app_bottom_sheet.dart';
+import 'package:spotiflac_android/widgets/album_detail_header.dart';
 import 'package:spotiflac_android/widgets/app_search_field.dart';
 import 'package:spotiflac_android/widgets/app_sliver_header.dart';
 import 'package:spotiflac_android/widgets/collection_scaffold.dart';
@@ -254,6 +255,37 @@ void main() {
     });
   });
 
+  group('AlbumDetailHeader', () {
+    testWidgets('keeps iOS toolbar controls clear of the screen edge', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: AppTheme.light().copyWith(platform: TargetPlatform.iOS),
+          home: Scaffold(
+            body: CustomScrollView(
+              slivers: const [
+                AlbumDetailHeader(
+                  title: 'Album',
+                  expandedHeight: 500,
+                  showTitleInAppBar: false,
+                  background: ColoredBox(color: Colors.orange),
+                  appBarActions: [SizedBox.square(dimension: 48)],
+                ),
+              ],
+            ),
+          ),
+        ),
+      );
+
+      final appBar = tester.widget<SliverAppBar>(find.byType(SliverAppBar));
+      expect(appBar.leadingWidth, kToolbarHeight + 12);
+      expect(appBar.actionsPadding, const EdgeInsets.only(right: 12));
+      final leadingPadding = appBar.leading! as Padding;
+      expect(leadingPadding.padding, const EdgeInsets.only(left: 12));
+    });
+  });
+
   group('AppSliverHeader', () {
     testWidgets('tab root variant shows the title without a back button', (
       tester,