Fix metadata consistency (Go->Flutter) and build optimization

- Backend: Return full metadata (Track, Disc, Year) from Tidal/Qobuz/Amazon download results
- Flutter: Use backend metadata for tagging converted M4A and history entries
- Fix: Duplicate convertTrack method in deezer.go
- Fix: Better error message for Deezer fallback failure
- Changed: Default service fallback to Tidal -> Qobuz -> Amazon
- Build: Re-enabled resource shrinking and minification for release build

lib/models/download_item.dart

@@ -13,6 +13,14 @@ enum DownloadStatus {
   skipped,
 }
 
+/// Error type enum for better error handling
+enum DownloadErrorType {
+  unknown,
+  notFound,    // Track not found on any service
+  rateLimit,   // Rate limited by service
+  network,     // Network/connection error
+}
+
 @JsonSerializable()
 class DownloadItem {
   final String id;
@@ -20,8 +28,10 @@ class DownloadItem {
   final String service;
   final DownloadStatus status;
   final double progress;
+  final double speedMBps; // Download speed in MB/s
   final String? filePath;
   final String? error;
+  final DownloadErrorType? errorType;
   final DateTime createdAt;
   final String? qualityOverride; // Override quality for this specific download
 
@@ -31,8 +41,10 @@ class DownloadItem {
     required this.service,
     this.status = DownloadStatus.queued,
     this.progress = 0.0,
+    this.speedMBps = 0.0,
     this.filePath,
     this.error,
+    this.errorType,
     required this.createdAt,
     this.qualityOverride,
   });
@@ -43,8 +55,10 @@ class DownloadItem {
     String? service,
     DownloadStatus? status,
     double? progress,
+    double? speedMBps,
     String? filePath,
     String? error,
+    DownloadErrorType? errorType,
     DateTime? createdAt,
     String? qualityOverride,
   }) {
@@ -54,13 +68,31 @@ class DownloadItem {
       service: service ?? this.service,
       status: status ?? this.status,
       progress: progress ?? this.progress,
+      speedMBps: speedMBps ?? this.speedMBps,
       filePath: filePath ?? this.filePath,
       error: error ?? this.error,
+      errorType: errorType ?? this.errorType,
       createdAt: createdAt ?? this.createdAt,
       qualityOverride: qualityOverride ?? this.qualityOverride,
     );
   }
 
+  /// Get user-friendly error message based on error type
+  String get errorMessage {
+    if (error == null) return '';
+    
+    switch (errorType) {
+      case DownloadErrorType.notFound:
+        return 'Song not found on any service';
+      case DownloadErrorType.rateLimit:
+        return 'Rate limit reached, try again later';
+      case DownloadErrorType.network:
+        return 'Connection failed, check your internet';
+      default:
+        return error ?? 'An error occurred';
+    }
+  }
+
   factory DownloadItem.fromJson(Map<String, dynamic> json) =>
       _$DownloadItemFromJson(json);
   Map<String, dynamic> toJson() => _$DownloadItemToJson(this);

lib/models/download_item.g.dart

@@ -14,8 +14,10 @@ DownloadItem _$DownloadItemFromJson(Map<String, dynamic> json) => DownloadItem(
       $enumDecodeNullable(_$DownloadStatusEnumMap, json['status']) ??
       DownloadStatus.queued,
   progress: (json['progress'] as num?)?.toDouble() ?? 0.0,
+  speedMBps: (json['speedMBps'] as num?)?.toDouble() ?? 0.0,
   filePath: json['filePath'] as String?,
   error: json['error'] as String?,
+  errorType: $enumDecodeNullable(_$DownloadErrorTypeEnumMap, json['errorType']),
   createdAt: DateTime.parse(json['createdAt'] as String),
   qualityOverride: json['qualityOverride'] as String?,
 );
@@ -27,8 +29,10 @@ Map<String, dynamic> _$DownloadItemToJson(DownloadItem instance) =>
       'service': instance.service,
       'status': _$DownloadStatusEnumMap[instance.status]!,
       'progress': instance.progress,
+      'speedMBps': instance.speedMBps,
       'filePath': instance.filePath,
       'error': instance.error,
+      'errorType': _$DownloadErrorTypeEnumMap[instance.errorType],
       'createdAt': instance.createdAt.toIso8601String(),
       'qualityOverride': instance.qualityOverride,
     };
@@ -41,3 +45,10 @@ const _$DownloadStatusEnumMap = {
   DownloadStatus.failed: 'failed',
   DownloadStatus.skipped: 'skipped',
 };
+
+const _$DownloadErrorTypeEnumMap = {
+  DownloadErrorType.unknown: 'unknown',
+  DownloadErrorType.notFound: 'notFound',
+  DownloadErrorType.rateLimit: 'rateLimit',
+  DownloadErrorType.network: 'network',
+};

lib/models/settings.g.dart

@@ -7,7 +7,7 @@ part of 'settings.dart';
 // **************************************************************************
 
 AppSettings _$AppSettingsFromJson(Map<String, dynamic> json) => AppSettings(
-  defaultService: json['defaultService'] as String? ?? 'tidal',
+  defaultService: json['defaultService'] as String? ?? 'qobuz',
   audioQuality: json['audioQuality'] as String? ?? 'LOSSLESS',
   filenameFormat: json['filenameFormat'] as String? ?? '{title} - {artist}',
   downloadDirectory: json['downloadDirectory'] as String? ?? '',

lib/models/track.dart

@@ -16,6 +16,7 @@ class Track {
   final int? trackNumber;
   final int? discNumber;
   final String? releaseDate;
+  final String? deezerId;
   final ServiceAvailability? availability;
 
   const Track({
@@ -30,6 +31,7 @@ class Track {
     this.trackNumber,
     this.discNumber,
     this.releaseDate,
+    this.deezerId,
     this.availability,
   });
 
@@ -42,17 +44,23 @@ class ServiceAvailability {
   final bool tidal;
   final bool qobuz;
   final bool amazon;
+  final bool deezer;
   final String? tidalUrl;
   final String? qobuzUrl;
   final String? amazonUrl;
+  final String? deezerUrl;
+  final String? deezerId;
 
   const ServiceAvailability({
     this.tidal = false,
     this.qobuz = false,
     this.amazon = false,
+    this.deezer = false,
     this.tidalUrl,
     this.qobuzUrl,
     this.amazonUrl,
+    this.deezerUrl,
+    this.deezerId,
   });
 
   factory ServiceAvailability.fromJson(Map<String, dynamic> json) =>

lib/models/track.g.dart

@@ -18,6 +18,7 @@ Track _$TrackFromJson(Map<String, dynamic> json) => Track(
   trackNumber: (json['trackNumber'] as num?)?.toInt(),
   discNumber: (json['discNumber'] as num?)?.toInt(),
   releaseDate: json['releaseDate'] as String?,
+  deezerId: json['deezerId'] as String?,
   availability: json['availability'] == null
       ? null
       : ServiceAvailability.fromJson(
@@ -37,6 +38,7 @@ Map<String, dynamic> _$TrackToJson(Track instance) => <String, dynamic>{
   'trackNumber': instance.trackNumber,
   'discNumber': instance.discNumber,
   'releaseDate': instance.releaseDate,
+  'deezerId': instance.deezerId,
   'availability': instance.availability,
 };
 
@@ -45,9 +47,12 @@ ServiceAvailability _$ServiceAvailabilityFromJson(Map<String, dynamic> json) =>
       tidal: json['tidal'] as bool? ?? false,
       qobuz: json['qobuz'] as bool? ?? false,
       amazon: json['amazon'] as bool? ?? false,
+      deezer: json['deezer'] as bool? ?? false,
       tidalUrl: json['tidalUrl'] as String?,
       qobuzUrl: json['qobuzUrl'] as String?,
       amazonUrl: json['amazonUrl'] as String?,
+      deezerUrl: json['deezerUrl'] as String?,
+      deezerId: json['deezerId'] as String?,
     );
 
 Map<String, dynamic> _$ServiceAvailabilityToJson(
@@ -56,7 +61,10 @@ Map<String, dynamic> _$ServiceAvailabilityToJson(
   'tidal': instance.tidal,
   'qobuz': instance.qobuz,
   'amazon': instance.amazon,
+  'deezer': instance.deezer,
   'tidalUrl': instance.tidalUrl,
   'qobuzUrl': instance.qobuzUrl,
   'amazonUrl': instance.amazonUrl,
+  'deezerUrl': instance.deezerUrl,
+  'deezerId': instance.deezerId,
 };