feat(download): add automatic lossy conversion

lib/models/settings.g.dart

@@ -60,6 +60,9 @@ AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
   locale: json['locale'] as String? ?? 'system',
   lyricsMode: json['lyricsMode'] as String? ?? 'embed',
   tidalHighFormat: json['tidalHighFormat'] as String? ?? 'mp3_320',
+  autoConvertDownloads: json['autoConvertDownloads'] as bool? ?? false,
+  autoConvertFormat: json['autoConvertFormat'] as String? ?? 'mp3',
+  autoConvertBitrate: json['autoConvertBitrate'] as String? ?? '320k',
   useAllFilesAccess: json['useAllFilesAccess'] as bool? ?? false,
   autoExportFailedDownloads:
       json['autoExportFailedDownloads'] as bool? ?? false,
@@ -145,6 +148,9 @@ Map<String, dynamic> _$AppSettingsToJson(
   'locale': instance.locale,
   'lyricsMode': instance.lyricsMode,
   'tidalHighFormat': instance.tidalHighFormat,
+  'autoConvertDownloads': instance.autoConvertDownloads,
+  'autoConvertFormat': instance.autoConvertFormat,
+  'autoConvertBitrate': instance.autoConvertBitrate,
   'useAllFilesAccess': instance.useAllFilesAccess,
   'autoExportFailedDownloads': instance.autoExportFailedDownloads,
   'downloadNetworkMode': instance.downloadNetworkMode,