refactor(layout): share responsiveScale and effectiveTextScale

The same clamp helpers were copied into four screens. They now live in
adaptive_layout.dart with identical bodies and clamp values.

lib/screens/artist_screen.dart

@@ -188,34 +188,15 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen>
   List<ArtistAlbum> _singlesBucket = const [];
   List<ArtistAlbum> _compilationsBucket = const [];
 
-  double _responsiveScale({
-    double min = 0.82,
-    double max = 1.08,
-    double baseShortestSide = 390,
-  }) {
-    final shortestSide = MediaQuery.sizeOf(context).shortestSide;
-    final scale = shortestSide / baseShortestSide;
-    if (scale < min) return min;
-    if (scale > max) return max;
-    return scale;
-  }
-
-  double _effectiveTextScale() {
-    final textScale = MediaQuery.textScalerOf(context).scale(1.0);
-    if (textScale < 1.0) return 1.0;
-    if (textScale > 1.4) return 1.4;
-    return textScale;
-  }
-
   double _artistAlbumTileSize() {
-    final scale = _responsiveScale(min: 0.82, max: 1.05);
-    final textScale = _effectiveTextScale();
+    final scale = responsiveScale(context: context, min: 0.82, max: 1.05);
+    final textScale = effectiveTextScale(context);
     return 140 * scale * (1 + (textScale - 1) * 0.12);
   }
 
   double _artistAlbumSectionHeight() {
     final tileSize = _artistAlbumTileSize();
-    final textScale = _effectiveTextScale();
+    final textScale = effectiveTextScale(context);
     return tileSize + 64 + ((textScale - 1) * 14);
   }
 

lib/screens/home_tab.dart

@@ -148,35 +148,15 @@ class _HomeTabState extends ConsumerState<HomeTab>
   List<Track>? _sortedTracksCache;
   List<int>? _sortedTrackIndexesCache;
 
-  double _responsiveScale({
-    required BuildContext context,
-    double min = 0.82,
-    double max = 1.08,
-    double baseShortestSide = 390,
-  }) {
-    final shortestSide = MediaQuery.sizeOf(context).shortestSide;
-    final scale = shortestSide / baseShortestSide;
-    if (scale < min) return min;
-    if (scale > max) return max;
-    return scale;
-  }
-
-  double _effectiveTextScale(BuildContext context) {
-    final textScale = MediaQuery.textScalerOf(context).scale(1.0);
-    if (textScale < 1.0) return 1.0;
-    if (textScale > 1.4) return 1.4;
-    return textScale;
-  }
-
   double _recentDownloadCoverSize(BuildContext context) {
-    final scale = _responsiveScale(context: context, min: 0.82, max: 1.25);
-    final textScale = _effectiveTextScale(context);
+    final scale = responsiveScale(context: context, min: 0.82, max: 1.25);
+    final textScale = effectiveTextScale(context);
     return 100 * scale * (1 + (textScale - 1) * 0.15);
   }
 
   double _recentDownloadsRowHeight(BuildContext context) {
     final coverSize = _recentDownloadCoverSize(context);
-    final textScale = _effectiveTextScale(context);
+    final textScale = effectiveTextScale(context);
     return coverSize + 28 + ((textScale - 1) * 8);
   }
 
@@ -184,8 +164,8 @@ class _HomeTabState extends ConsumerState<HomeTab>
     // Six phone-sized cards across an iPad made the feed look like a desktop
     // page zoomed out. A higher tablet cap gives roughly five generous cards
     // in portrait while leaving all phone sizes unchanged.
-    final scale = _responsiveScale(context: context, min: 0.82, max: 1.32);
-    final textScale = _effectiveTextScale(context);
+    final scale = responsiveScale(context: context, min: 0.82, max: 1.32);
+    final textScale = effectiveTextScale(context);
     final size = 145 * scale * (1 + (textScale - 1) * 0.12);
     // Landscape tablets are short: one carousel row should not take over a
     // third of the screen. Portrait and phone heights never reach this cap.
@@ -195,7 +175,7 @@ class _HomeTabState extends ConsumerState<HomeTab>
 
   double _exploreSectionHeight(BuildContext context) {
     final cardSize = _exploreCardSize(context);
-    final textScale = _effectiveTextScale(context);
+    final textScale = effectiveTextScale(context);
     return cardSize + 58 + ((textScale - 1) * 12);
   }
 

lib/screens/queue_tab.dart

@@ -222,17 +222,10 @@ class _QueueTabState extends ConsumerState<QueueTab> {
   _queueLibraryPageDataCache = {};
   DateTime? _lastBlankLibraryRepairAt;
 
-  double _effectiveTextScale() {
-    final textScale = MediaQuery.textScalerOf(context).scale(1.0);
-    if (textScale < 1.0) return 1.0;
-    if (textScale > 1.4) return 1.4;
-    return textScale;
-  }
-
   double _queueCoverSize() {
     final shortestSide = MediaQuery.sizeOf(context).shortestSide;
     final scale = (shortestSide / 390).clamp(0.82, 1.0);
-    final textScale = _effectiveTextScale();
+    final textScale = effectiveTextScale(context);
     return (56 * scale * (1 + ((textScale - 1) * 0.12))).clamp(46.0, 56.0);
   }
 

lib/screens/tutorial_screen.dart

@@ -3,6 +3,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/l10n/l10n.dart';
+import 'package:spotiflac_android/utils/adaptive_layout.dart';
 import 'package:spotiflac_android/widgets/scroll_edge_fade.dart';
 import 'package:spotiflac_android/widgets/app_icon_button.dart';
 import 'package:spotiflac_android/widgets/app_loading_indicator.dart';
@@ -22,26 +23,6 @@ class _TutorialScreenState extends ConsumerState<TutorialScreen> {
   int _currentPage = 0;
   static const int _totalPages = 6;
 
-  double _responsiveScale({
-    required BuildContext context,
-    double min = 0.82,
-    double max = 1.08,
-    double baseShortestSide = 390,
-  }) {
-    final shortestSide = MediaQuery.sizeOf(context).shortestSide;
-    final scale = shortestSide / baseShortestSide;
-    if (scale < min) return min;
-    if (scale > max) return max;
-    return scale;
-  }
-
-  double _effectiveTextScale(BuildContext context) {
-    final textScale = MediaQuery.textScalerOf(context).scale(1.0);
-    if (textScale < 1.0) return 1.0;
-    if (textScale > 1.4) return 1.4;
-    return textScale;
-  }
-
   @override
   void dispose() {
     _pageController.dispose();
@@ -81,8 +62,8 @@ class _TutorialScreenState extends ConsumerState<TutorialScreen> {
     final colorScheme = Theme.of(context).colorScheme;
     final l10n = context.l10n;
     final isLastPage = _currentPage == _totalPages - 1;
-    final scale = _responsiveScale(context: context, min: 0.86, max: 1.05);
-    final textScale = _effectiveTextScale(context);
+    final scale = responsiveScale(context: context, min: 0.86, max: 1.05);
+    final textScale = effectiveTextScale(context);
     final topBarPaddingH = 24 * scale;
     final topBarPaddingV = 16 * scale;
     final pageIndicatorHeight = 8 * scale;

lib/utils/adaptive_layout.dart

@@ -115,3 +115,25 @@ double wideListInset(
   MediaQuery.sizeOf(context).width,
   contentMaxWidth: contentMaxWidth,
 );
+
+/// Scales fixed sizes with the shortest screen side, clamped to [min]..[max].
+double responsiveScale({
+  required BuildContext context,
+  double min = 0.82,
+  double max = 1.08,
+  double baseShortestSide = 390,
+}) {
+  final shortestSide = MediaQuery.sizeOf(context).shortestSide;
+  final scale = shortestSide / baseShortestSide;
+  if (scale < min) return min;
+  if (scale > max) return max;
+  return scale;
+}
+
+/// The system text scale clamped to 1.0..1.4 for fixed-height layouts.
+double effectiveTextScale(BuildContext context) {
+  final textScale = MediaQuery.textScalerOf(context).scale(1.0);
+  if (textScale < 1.0) return 1.0;
+  if (textScale > 1.4) return 1.4;
+  return textScale;
+}