feat(library): add bit depth quality label mode

test/audio_quality_badge_policy_test.dart

@@ -46,6 +46,33 @@ void main() {
         ),
         AppSettings.libraryQualityLabelBitDepthBitrate,
       );
+      expect(
+        normalizeLibraryQualityLabelMode(
+          AppSettings.libraryQualityLabelBitDepthOnly,
+        ),
+        AppSettings.libraryQualityLabelBitDepthOnly,
+      );
+    });
+
+    test('shows only bit depth when requested', () {
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelBitDepthOnly,
+          format: 'flac',
+          bitrateKbps: 1411,
+          bitDepth: 16,
+          sampleRate: 44100,
+        ),
+        '16-bit',
+      );
+      expect(
+        buildLibraryAudioQualityLabel(
+          mode: AppSettings.libraryQualityLabelBitDepthOnly,
+          format: 'flac',
+          storedQuality: '24-bit/96kHz',
+        ),
+        '24-bit',
+      );
     });
 
     test('restores legacy bit depth and sample rate labels', () {

test/models_and_utils_test.dart

@@ -767,7 +767,7 @@ void main() {
         lyricsAppleElrcWordSync: true,
         deduplicateDownloads: false,
         allowQualityVariants: true,
-        libraryQualityLabelMode: AppSettings.libraryQualityLabelBitDepthBitrate,
+        libraryQualityLabelMode: AppSettings.libraryQualityLabelBitDepthOnly,
         clearDownloadFallbackExtensionIds: true,
         clearSearchProvider: true,
         clearHomeFeedProvider: true,
@@ -781,7 +781,7 @@ void main() {
       expect(updated.allowQualityVariants, isTrue);
       expect(
         updated.libraryQualityLabelMode,
-        AppSettings.libraryQualityLabelBitDepthBitrate,
+        AppSettings.libraryQualityLabelBitDepthOnly,
       );
       expect(updated.downloadFallbackExtensionIds, isNull);
       expect(updated.searchProvider, isNull);
@@ -812,7 +812,7 @@ void main() {
         autoConvertDownloads: true,
         autoConvertFormat: 'opus',
         autoConvertBitrate: '192k',
-        libraryQualityLabelMode: AppSettings.libraryQualityLabelBitDepthBitrate,
+        libraryQualityLabelMode: AppSettings.libraryQualityLabelBitDepthOnly,
       );
 
       final decoded = AppSettings.fromJson(settings.toJson());
@@ -834,7 +834,7 @@ void main() {
       expect(decoded.lastSeenVersion, '4.5.0');
       expect(
         decoded.libraryQualityLabelMode,
-        AppSettings.libraryQualityLabelBitDepthBitrate,
+        AppSettings.libraryQualityLabelBitDepthOnly,
       );
       expect(decoded.deduplicateDownloads, isFalse);
       expect(decoded.allowQualityVariants, isTrue);