feat: v3.5.0 - SAF storage, onboarding redesign, library scan fixes

- SAF Storage Access Framework for Android 10+ downloads
- Redesigned Setup/Tutorial screens with Material 3 Expressive
- Library scan hero card now shows real-time scanned count
- Library folder picker uses SAF (no MANAGE_EXTERNAL_STORAGE needed)
- SAF migration prompt for users updating from pre-SAF versions
- Home feed caching, donate page, per-app language support
- Merged 3.6.0-beta.1 changelog entries into 3.5.0

lib/models/settings.dart

@@ -43,6 +43,9 @@ class AppSettings {
   final bool localLibraryEnabled; // Enable local library scanning
   final String localLibraryPath; // Path to scan for audio files
   final bool localLibraryShowDuplicates; // Show indicator when searching for existing tracks
+  
+  // Tutorial/Onboarding
+  final bool hasCompletedTutorial; // Track if user has completed the app tutorial
 
   const AppSettings({
     this.defaultService = 'tidal',
@@ -83,6 +86,8 @@ class AppSettings {
     this.localLibraryEnabled = false,
     this.localLibraryPath = '',
     this.localLibraryShowDuplicates = true,
+    // Tutorial default
+    this.hasCompletedTutorial = false,
   });
 
   AppSettings copyWith({
@@ -125,6 +130,8 @@ class AppSettings {
     bool? localLibraryEnabled,
     String? localLibraryPath,
     bool? localLibraryShowDuplicates,
+    // Tutorial
+    bool? hasCompletedTutorial,
   }) {
     return AppSettings(
       defaultService: defaultService ?? this.defaultService,
@@ -165,6 +172,8 @@ class AppSettings {
       localLibraryEnabled: localLibraryEnabled ?? this.localLibraryEnabled,
       localLibraryPath: localLibraryPath ?? this.localLibraryPath,
       localLibraryShowDuplicates: localLibraryShowDuplicates ?? this.localLibraryShowDuplicates,
+      // Tutorial
+      hasCompletedTutorial: hasCompletedTutorial ?? this.hasCompletedTutorial,
     );
   }
 

lib/models/settings.g.dart

@@ -48,6 +48,7 @@ AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
   localLibraryPath: json['localLibraryPath'] as String? ?? '',
   localLibraryShowDuplicates:
       json['localLibraryShowDuplicates'] as bool? ?? true,
+  hasCompletedTutorial: json['hasCompletedTutorial'] as bool? ?? false,
 );
 
 Map<String, dynamic> _$AppSettingsToJson(AppSettings instance) =>
@@ -89,4 +90,5 @@ Map<String, dynamic> _$AppSettingsToJson(AppSettings instance) =>
       'localLibraryEnabled': instance.localLibraryEnabled,
       'localLibraryPath': instance.localLibraryPath,
       'localLibraryShowDuplicates': instance.localLibraryShowDuplicates,
+      'hasCompletedTutorial': instance.hasCompletedTutorial,
     };