feat: add FLAC/ALAC bidirectional lossless conversion support

- Add _convertToAlac() and _convertToFlac() in ffmpeg_service with
  single-pass FFmpeg encoding, metadata tags, and cover art embedding
- Wire lossless formats (ALAC, FLAC) into single-track convert sheet
  with dynamic format list based on source format, hidden bitrate for
  lossless targets, and lossless hint text
- Add lossless conversion to batch convert UI in downloaded_album,
  local_album, and queue_tab screens with lossy-source filtering
- Fix M4A quality probe in Go backend: increase audio sample entry
  buffer from 24 to 32 bytes, read sample rate from correct offset
  (bytes 28-29) and bit depth from samplesize field (bytes 22-23)
- Add l10n keys for lossless confirm dialogs and hints (en, id)

lib/l10n/app_localizations.dart

@@ -3883,7 +3883,7 @@ abstract class AppLocalizations {
   /// Subtitle for convert format menu item
   ///
   /// In en, this message translates to:
-  /// **'Convert to MP3 or Opus'**
+  /// **'Convert to MP3, Opus, ALAC, or FLAC'**
   String get trackConvertFormatSubtitle;
 
   /// Title of convert bottom sheet
@@ -3920,6 +3920,21 @@ abstract class AppLocalizations {
     String bitrate,
   );
 
+  /// Confirmation dialog message for lossless-to-lossless conversion
+  ///
+  /// In en, this message translates to:
+  /// **'Convert from {sourceFormat} to {targetFormat}? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.'**
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  );
+
+  /// Hint shown when converting between lossless formats
+  ///
+  /// In en, this message translates to:
+  /// **'Lossless conversion — no quality loss'**
+  String get trackConvertLosslessHint;
+
   /// Snackbar while converting
   ///
   /// In en, this message translates to:
@@ -4290,6 +4305,12 @@ abstract class AppLocalizations {
     String bitrate,
   );
 
+  /// Confirmation dialog message for lossless batch conversion
+  ///
+  /// In en, this message translates to:
+  /// **'Convert {count} {count, plural, =1{track} other{tracks}} to {format}? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.'**
+  String selectionBatchConvertConfirmMessageLossless(int count, String format);
+
   /// Snackbar during batch conversion progress
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_de.dart

@@ -2226,6 +2226,18 @@ class AppLocalizationsDe extends AppLocalizations {
     return 'Konvertieren von $sourceFormat in $targetFormat bei $bitrate?\n\nDie Originaldatei wird nach der Konvertierung gelöscht.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Konvertiere Audio...';
 
@@ -2480,6 +2492,17 @@ class AppLocalizationsDe extends AppLocalizations {
     return 'Konvertiere $count $format $_temp0 zu $bitrate?\n\nOriginaldateien werden nach der Konvertierung gelöscht.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Konvertiere $current von $total...';

lib/l10n/app_localizations_en.dart

@@ -2176,7 +2176,8 @@ class AppLocalizationsEn extends AppLocalizations {
   String get trackConvertFormat => 'Convert Format';
 
   @override
-  String get trackConvertFormatSubtitle => 'Convert to MP3 or Opus';
+  String get trackConvertFormatSubtitle =>
+      'Convert to MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2199,6 +2200,18 @@ class AppLocalizationsEn extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2452,6 +2465,17 @@ class AppLocalizationsEn extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_es.dart

@@ -2176,7 +2176,8 @@ class AppLocalizationsEs extends AppLocalizations {
   String get trackConvertFormat => 'Convert Format';
 
   @override
-  String get trackConvertFormatSubtitle => 'Convert to MP3 or Opus';
+  String get trackConvertFormatSubtitle =>
+      'Convert to MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2199,6 +2200,18 @@ class AppLocalizationsEs extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2452,6 +2465,17 @@ class AppLocalizationsEs extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_fr.dart

@@ -2201,6 +2201,18 @@ class AppLocalizationsFr extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2454,6 +2466,17 @@ class AppLocalizationsFr extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_hi.dart

@@ -2199,6 +2199,18 @@ class AppLocalizationsHi extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2452,6 +2464,17 @@ class AppLocalizationsHi extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_id.dart

@@ -2183,7 +2183,8 @@ class AppLocalizationsId extends AppLocalizations {
   String get trackConvertFormat => 'Convert Format';
 
   @override
-  String get trackConvertFormatSubtitle => 'Convert to MP3 or Opus';
+  String get trackConvertFormatSubtitle =>
+      'Konversi ke MP3, Opus, ALAC, atau FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2206,6 +2207,18 @@ class AppLocalizationsId extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Konversi dari $sourceFormat ke $targetFormat? (Lossless — tanpa kehilangan kualitas)\n\nFile asli akan dihapus setelah konversi.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Konversi lossless — tanpa kehilangan kualitas';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2459,6 +2472,17 @@ class AppLocalizationsId extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_ja.dart

@@ -2186,6 +2186,18 @@ class AppLocalizationsJa extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'オーディオを変換中...';
 
@@ -2439,6 +2451,17 @@ class AppLocalizationsJa extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_ko.dart

@@ -2179,6 +2179,18 @@ class AppLocalizationsKo extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2432,6 +2444,17 @@ class AppLocalizationsKo extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_nl.dart

@@ -2199,6 +2199,18 @@ class AppLocalizationsNl extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2452,6 +2464,17 @@ class AppLocalizationsNl extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_pt.dart

@@ -2176,7 +2176,8 @@ class AppLocalizationsPt extends AppLocalizations {
   String get trackConvertFormat => 'Convert Format';
 
   @override
-  String get trackConvertFormatSubtitle => 'Convert to MP3 or Opus';
+  String get trackConvertFormatSubtitle =>
+      'Convert to MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2199,6 +2200,18 @@ class AppLocalizationsPt extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2452,6 +2465,17 @@ class AppLocalizationsPt extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_ru.dart

@@ -2252,6 +2252,18 @@ class AppLocalizationsRu extends AppLocalizations {
     return 'Конвертировать из $sourceFormat в $targetFormat $bitrate?\n\nОригинальный файл будет удален после конвертации.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Конвертация аудио...';
 
@@ -2511,6 +2523,17 @@ class AppLocalizationsRu extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Конвертация $current из $total...';

lib/l10n/app_localizations_tr.dart

@@ -2211,6 +2211,18 @@ class AppLocalizationsTr extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2464,6 +2476,17 @@ class AppLocalizationsTr extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/app_localizations_zh.dart

@@ -2176,7 +2176,8 @@ class AppLocalizationsZh extends AppLocalizations {
   String get trackConvertFormat => 'Convert Format';
 
   @override
-  String get trackConvertFormatSubtitle => 'Convert to MP3 or Opus';
+  String get trackConvertFormatSubtitle =>
+      'Convert to MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2199,6 +2200,18 @@ class AppLocalizationsZh extends AppLocalizations {
     return 'Convert from $sourceFormat to $targetFormat at $bitrate?\n\nThe original file will be deleted after conversion.';
   }
 
+  @override
+  String trackConvertConfirmMessageLossless(
+    String sourceFormat,
+    String targetFormat,
+  ) {
+    return 'Convert from $sourceFormat to $targetFormat? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.';
+  }
+
+  @override
+  String get trackConvertLosslessHint =>
+      'Lossless conversion — no quality loss';
+
   @override
   String get trackConvertConverting => 'Converting audio...';
 
@@ -2452,6 +2465,17 @@ class AppLocalizationsZh extends AppLocalizations {
     return 'Convert $count $_temp0 to $format at $bitrate?\n\nOriginal files will be deleted after conversion.';
   }
 
+  @override
+  String selectionBatchConvertConfirmMessageLossless(int count, String format) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Convert $count $_temp0 to $format? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.';
+  }
+
   @override
   String selectionBatchConvertProgress(int current, int total) {
     return 'Converting $current of $total...';

lib/l10n/arb/app_en.arb

@@ -2873,7 +2873,7 @@
   "@trackConvertFormat": {
     "description": "Menu item - convert audio format"
   },
-  "trackConvertFormatSubtitle": "Convert to MP3 or Opus",
+  "trackConvertFormatSubtitle": "Convert to MP3, Opus, ALAC, or FLAC",
   "@trackConvertFormatSubtitle": {
     "description": "Subtitle for convert format menu item"
   },
@@ -2908,6 +2908,22 @@
       }
     }
   },
+  "trackConvertConfirmMessageLossless": "Convert from {sourceFormat} to {targetFormat}? (Lossless — no quality loss)\n\nThe original file will be deleted after conversion.",
+  "@trackConvertConfirmMessageLossless": {
+    "description": "Confirmation dialog message for lossless-to-lossless conversion",
+    "placeholders": {
+      "sourceFormat": {
+        "type": "String"
+      },
+      "targetFormat": {
+        "type": "String"
+      }
+    }
+  },
+  "trackConvertLosslessHint": "Lossless conversion — no quality loss",
+  "@trackConvertLosslessHint": {
+    "description": "Hint shown when converting between lossless formats"
+  },
   "trackConvertConverting": "Converting audio...",
   "@trackConvertConverting": {
     "description": "Snackbar while converting"
@@ -3259,6 +3275,18 @@
       }
     }
   },
+  "selectionBatchConvertConfirmMessageLossless": "Convert {count} {count, plural, =1{track} other{tracks}} to {format}? (Lossless — no quality loss)\n\nOriginal files will be deleted after conversion.",
+  "@selectionBatchConvertConfirmMessageLossless": {
+    "description": "Confirmation dialog message for lossless batch conversion",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      },
+      "format": {
+        "type": "String"
+      }
+    }
+  },
   "selectionBatchConvertProgress": "Converting {current} of {total}...",
   "@selectionBatchConvertProgress": {
     "description": "Snackbar during batch conversion progress",

lib/l10n/arb/app_id.arb

@@ -2809,7 +2809,7 @@
   "@trackConvertFormat": {
     "description": "Menu item - convert audio format"
   },
-  "trackConvertFormatSubtitle": "Convert to MP3 or Opus",
+  "trackConvertFormatSubtitle": "Konversi ke MP3, Opus, ALAC, atau FLAC",
   "@trackConvertFormatSubtitle": {
     "description": "Subtitle for convert format menu item"
   },
@@ -2844,6 +2844,22 @@
       }
     }
   },
+  "trackConvertConfirmMessageLossless": "Konversi dari {sourceFormat} ke {targetFormat}? (Lossless — tanpa kehilangan kualitas)\n\nFile asli akan dihapus setelah konversi.",
+  "@trackConvertConfirmMessageLossless": {
+    "description": "Confirmation dialog message for lossless-to-lossless conversion",
+    "placeholders": {
+      "sourceFormat": {
+        "type": "String"
+      },
+      "targetFormat": {
+        "type": "String"
+      }
+    }
+  },
+  "trackConvertLosslessHint": "Konversi lossless — tanpa kehilangan kualitas",
+  "@trackConvertLosslessHint": {
+    "description": "Hint shown when converting between lossless formats"
+  },
   "trackConvertConverting": "Converting audio...",
   "@trackConvertConverting": {
     "description": "Snackbar while converting"