fix(library): retain Opus badges when bitrate is missing

lib/models/unified_library_item.dart

@@ -110,6 +110,8 @@ class UnifiedLibraryItem {
       return buildLibraryAudioQualityLabel(
         mode: mode,
         format: history.format,
+        filePath: history.filePath,
+        fileName: history.safFileName,
         bitrateKbps: history.bitrate,
         bitDepth: history.bitDepth,
         sampleRate: history.sampleRate,
@@ -122,6 +124,7 @@ class UnifiedLibraryItem {
       return buildLibraryAudioQualityLabel(
         mode: mode,
         format: local.format,
+        filePath: local.filePath,
         bitrateKbps: local.bitrate,
         bitDepth: local.bitDepth,
         sampleRate: local.sampleRate,

lib/screens/downloaded_album_screen.dart

@@ -495,6 +495,8 @@ class _DownloadedAlbumScreenState extends ConsumerState<DownloadedAlbumScreen>
     String? label(DownloadHistoryItem track) => buildLibraryAudioQualityLabel(
       mode: mode,
       format: track.format,
+      filePath: track.filePath,
+      fileName: track.safFileName,
       bitrateKbps: track.bitrate,
       bitDepth: track.bitDepth,
       sampleRate: track.sampleRate,

lib/screens/local_album_screen.dart

@@ -323,6 +323,7 @@ class _LocalAlbumScreenState extends ConsumerState<LocalAlbumScreen>
     String? label(LocalLibraryItem track) => buildLibraryAudioQualityLabel(
       mode: mode,
       format: track.format,
+      filePath: track.filePath,
       bitrateKbps: track.bitrate,
       bitDepth: track.bitDepth,
       sampleRate: track.sampleRate,

lib/utils/audio_quality_badge_policy.dart

@@ -49,11 +49,16 @@ String? _libraryFileFormatLabel(String? format) {
 String? buildLibraryAudioQualityLabel({
   required String mode,
   String? format,
+  String? filePath,
+  String? fileName,
   int? bitrateKbps,
   int? bitDepth,
   int? sampleRate,
   String? storedQuality,
 }) {
+  final effectiveFormat =
+      normalizeOptionalString(format) ??
+      audioFormatForPath(filePath, fileName: fileName);
   final stored = normalizeOptionalString(storedQuality);
   final storedBitrate = _bitrateFromStoredQuality(stored);
   final storedBitDepth = _bitDepthFromStoredQuality(stored);
@@ -64,7 +69,10 @@ String? buildLibraryAudioQualityLabel({
       ? bitDepth
       : storedBitDepth;
   final bitrateLabel = effectiveBitrate != null
-      ? buildDisplayAudioQuality(bitrateKbps: effectiveBitrate, format: format)
+      ? buildDisplayAudioQuality(
+          bitrateKbps: effectiveBitrate,
+          format: effectiveFormat,
+        )
       : null;
   final bitDepthLabel =
       bitDepth != null && bitDepth > 0 && sampleRate != null && sampleRate > 0
@@ -76,11 +84,14 @@ String? buildLibraryAudioQualityLabel({
   final normalizedMode = normalizeLibraryQualityLabelMode(mode);
 
   if (normalizedMode == AppSettings.libraryQualityLabelFileFormat) {
-    return _libraryFileFormatLabel(format);
+    return _libraryFileFormatLabel(effectiveFormat);
   }
 
-  if (isLossyAudioFormat(format)) {
-    return bitrateLabel;
+  if (isLossyAudioFormat(effectiveFormat)) {
+    // Older rows may know the codec before their bitrate has been backfilled.
+    // Keep a useful badge without showing stale lossless specs or inventing a
+    // bitrate from the user's current download/conversion setting.
+    return bitrateLabel ?? _libraryFileFormatLabel(effectiveFormat);
   }
 
   return switch (normalizedMode) {

test/audio_quality_badge_policy_test.dart

@@ -1,8 +1,50 @@
 import 'package:flutter_test/flutter_test.dart';
 import 'package:spotiflac_android/models/settings.dart';
+import 'package:spotiflac_android/models/unified_library_item.dart';
+import 'package:spotiflac_android/providers/download_history_provider.dart';
+import 'package:spotiflac_android/services/library_database.dart';
 import 'package:spotiflac_android/utils/audio_quality_badge_policy.dart';
 
 void main() {
+  test(
+    'Library history and local cards retain labels for legacy Opus rows',
+    () {
+      final history = UnifiedLibraryItem.fromDownloadHistory(
+        DownloadHistoryItem(
+          id: 'history-song',
+          trackName: 'Song',
+          artistName: 'Artist',
+          albumName: 'Album',
+          filePath: 'content://music/document/42',
+          safFileName: 'Song.opus',
+          quality: '16-bit/44.1kHz',
+          service: 'example',
+          downloadedAt: DateTime(2026),
+        ),
+      );
+      final local = UnifiedLibraryItem.fromLocalLibrary(
+        LocalLibraryItem(
+          id: 'local-song',
+          trackName: 'Song',
+          artistName: 'Artist',
+          albumName: 'Album',
+          filePath: '/music/Song.opus',
+          scannedAt: DateTime(2026),
+        ),
+      );
+      for (final item in [history, local]) {
+        expect(
+          item.qualityForMode(AppSettings.libraryQualityLabelBitDepth),
+          'OPUS',
+        );
+        expect(
+          item.qualityForMode(AppSettings.libraryQualityLabelBitrate),
+          'OPUS',
+        );
+      }
+    },
+  );
+
   group('Library audio quality badge color', () {
     test('keeps legacy 24-bit labels highlighted', () {
       expect(shouldHighlightAudioQualityBadge('24-bit/96kHz'), isTrue);
@@ -25,6 +67,77 @@ void main() {
   });
 
   group('Library audio quality label mode', () {
+    test('keeps an Opus badge when bitrate has not been backfilled', () {
+      for (final mode in [
+        AppSettings.libraryQualityLabelBitrate,
+        AppSettings.libraryQualityLabelBitDepth,
+        AppSettings.libraryQualityLabelBitDepthOnly,
+        AppSettings.libraryQualityLabelBitDepthBitrate,
+        AppSettings.libraryQualityLabelFileFormat,
+      ]) {
+        expect(
+          buildLibraryAudioQualityLabel(
+            mode: mode,
+            format: 'opus',
+            bitDepth: 16,
+            sampleRate: 44100,
+            storedQuality: '16-bit/44.1kHz',
+          ),
+          'OPUS',
+          reason: mode,
+        );
+      }
+    });
+
+    test('uses stored Opus bitrate until measured bitrate is available', () {
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelBitDepth,
+          format: 'opus',
+          storedQuality: 'OPUS 320kbps',
+        ),
+        'OPUS 320kbps',
+      );
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelBitDepth,
+          format: 'opus',
+          bitrateKbps: 256,
+          storedQuality: 'OPUS 320kbps',
+        ),
+        'OPUS 256kbps',
+      );
+      expect(formatLibraryGridAudioQualityLabel('OPUS 320kbps'), '320k');
+      expect(formatLibraryGridAudioQualityLabel('OPUS'), 'OPUS');
+    });
+
+    test('uses the path or SAF name when a legacy row has no format', () {
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelBitDepth,
+          filePath: '/music/Song.opus',
+          storedQuality: '16-bit/44.1kHz',
+        ),
+        'OPUS',
+      );
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelBitrate,
+          filePath: 'content://music/document/42',
+          fileName: 'Song.OPUS',
+        ),
+        'OPUS',
+      );
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelFileFormat,
+          format: 'alac',
+          filePath: '/music/Song.m4a',
+        ),
+        'ALAC',
+      );
+    });
+
     test('uses measured bitrate by default', () {
       expect(
         buildLibraryAudioQualityLabel(