feat: multi-select batch delete and album grouping in history

- Add multi-select mode with long-press to select tracks
- Add bottom action bar for selection (Material 3 style)
- Add filter tabs: All/Albums/Singles
- Add album grouping view when Albums filter selected
- Add DownloadedAlbumScreen for viewing tracks in an album
- Reactive UI updates when tracks deleted
- Auto-pop when album has <2 tracks
- Update issue templates with (Stable Version) text
- Bump version to 2.2.8

lib/models/settings.dart

@@ -18,6 +18,7 @@ class AppSettings {
   final bool hasSearchedBefore; // Hide helper text after first search
   final String folderOrganization; // none, artist, album, artist_album
   final String historyViewMode; // list, grid
+  final String historyFilterMode; // all, albums, singles
   final bool askQualityBeforeDownload; // Show quality picker before each download
   final String spotifyClientId; // Custom Spotify client ID (empty = use default)
   final String spotifyClientSecret; // Custom Spotify client secret (empty = use default)
@@ -40,6 +41,7 @@ class AppSettings {
     this.hasSearchedBefore = false, // Default: show helper text
     this.folderOrganization = 'none', // Default: no folder organization
     this.historyViewMode = 'grid', // Default: grid view
+    this.historyFilterMode = 'all', // Default: show all
     this.askQualityBeforeDownload = true, // Default: ask quality before download
     this.spotifyClientId = '', // Default: use built-in credentials
     this.spotifyClientSecret = '', // Default: use built-in credentials
@@ -63,6 +65,7 @@ class AppSettings {
     bool? hasSearchedBefore,
     String? folderOrganization,
     String? historyViewMode,
+    String? historyFilterMode,
     bool? askQualityBeforeDownload,
     String? spotifyClientId,
     String? spotifyClientSecret,
@@ -85,6 +88,7 @@ class AppSettings {
       hasSearchedBefore: hasSearchedBefore ?? this.hasSearchedBefore,
       folderOrganization: folderOrganization ?? this.folderOrganization,
       historyViewMode: historyViewMode ?? this.historyViewMode,
+      historyFilterMode: historyFilterMode ?? this.historyFilterMode,
       askQualityBeforeDownload: askQualityBeforeDownload ?? this.askQualityBeforeDownload,
       spotifyClientId: spotifyClientId ?? this.spotifyClientId,
       spotifyClientSecret: spotifyClientSecret ?? this.spotifyClientSecret,

lib/models/settings.g.dart

@@ -21,6 +21,7 @@ AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
   hasSearchedBefore: json['hasSearchedBefore'] as bool? ?? false,
   folderOrganization: json['folderOrganization'] as String? ?? 'none',
   historyViewMode: json['historyViewMode'] as String? ?? 'grid',
+  historyFilterMode: json['historyFilterMode'] as String? ?? 'all',
   askQualityBeforeDownload: json['askQualityBeforeDownload'] as bool? ?? true,
   spotifyClientId: json['spotifyClientId'] as String? ?? '',
   spotifyClientSecret: json['spotifyClientSecret'] as String? ?? '',
@@ -46,6 +47,7 @@ Map<String, dynamic> _$AppSettingsToJson(AppSettings instance) =>
       'hasSearchedBefore': instance.hasSearchedBefore,
       'folderOrganization': instance.folderOrganization,
       'historyViewMode': instance.historyViewMode,
+      'historyFilterMode': instance.historyFilterMode,
       'askQualityBeforeDownload': instance.askQualityBeforeDownload,
       'spotifyClientId': instance.spotifyClientId,
       'spotifyClientSecret': instance.spotifyClientSecret,