feat: add stable cover cache keys, Qobuz album-search fallback, metadata filters and extended sort options

- Introduce coverCacheKey parameter through Go backend and Kotlin bridge for stable SAF cover caching
- Add MetadataFromFilename flag to skip filename-only metadata and retry via temp-file copy
- Add Qobuz album-search fallback between API search and store scraping
- Extract buildReEnrichFFmpegMetadata to skip empty metadata fields
- Add metadata completeness filter (complete, missing year/genre/album artist)
- Add sort modes: artist, album, release date, genre (asc/desc)
- Prune stale library cover cache files after full scan
- Skip empty values and zero track/disc numbers in FFmpeg metadata
- Add new l10n keys for metadata filter and sort options

lib/l10n/app_localizations.dart

@@ -3478,6 +3478,42 @@ abstract class AppLocalizations {
   /// **'Format'**
   String get libraryFilterFormat;
 
+  /// Filter section - metadata completeness
+  ///
+  /// In en, this message translates to:
+  /// **'Metadata'**
+  String get libraryFilterMetadata;
+
+  /// Filter option - items with complete metadata
+  ///
+  /// In en, this message translates to:
+  /// **'Complete metadata'**
+  String get libraryFilterMetadataComplete;
+
+  /// Filter option - items missing any tracked metadata field
+  ///
+  /// In en, this message translates to:
+  /// **'Missing any metadata'**
+  String get libraryFilterMetadataMissingAny;
+
+  /// Filter option - items missing release year/date
+  ///
+  /// In en, this message translates to:
+  /// **'Missing year'**
+  String get libraryFilterMetadataMissingYear;
+
+  /// Filter option - items missing genre
+  ///
+  /// In en, this message translates to:
+  /// **'Missing genre'**
+  String get libraryFilterMetadataMissingGenre;
+
+  /// Filter option - items missing album artist
+  ///
+  /// In en, this message translates to:
+  /// **'Missing album artist'**
+  String get libraryFilterMetadataMissingAlbumArtist;
+
   /// Filter section - sort order
   ///
   /// In en, this message translates to:
@@ -3496,6 +3532,30 @@ abstract class AppLocalizations {
   /// **'Oldest'**
   String get libraryFilterSortOldest;
 
+  /// Sort option - album ascending
+  ///
+  /// In en, this message translates to:
+  /// **'Album (A-Z)'**
+  String get libraryFilterSortAlbumAsc;
+
+  /// Sort option - album descending
+  ///
+  /// In en, this message translates to:
+  /// **'Album (Z-A)'**
+  String get libraryFilterSortAlbumDesc;
+
+  /// Sort option - genre ascending
+  ///
+  /// In en, this message translates to:
+  /// **'Genre (A-Z)'**
+  String get libraryFilterSortGenreAsc;
+
+  /// Sort option - genre descending
+  ///
+  /// In en, this message translates to:
+  /// **'Genre (Z-A)'**
+  String get libraryFilterSortGenreDesc;
+
   /// Relative time - less than a minute ago
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_de.dart

@@ -1930,6 +1930,24 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sortieren';
 
@@ -1939,6 +1957,18 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Älteste';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Gerade eben';
 

lib/l10n/app_localizations_en.dart

@@ -1902,6 +1902,24 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1911,6 +1929,18 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_es.dart

@@ -1902,6 +1902,24 @@ class AppLocalizationsEs extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1911,6 +1929,18 @@ class AppLocalizationsEs extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_fr.dart

@@ -1904,6 +1904,24 @@ class AppLocalizationsFr extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1913,6 +1931,18 @@ class AppLocalizationsFr extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_hi.dart

@@ -1902,6 +1902,24 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1911,6 +1929,18 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_id.dart

@@ -1912,6 +1912,24 @@ class AppLocalizationsId extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1921,6 +1939,18 @@ class AppLocalizationsId extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_ja.dart

@@ -1889,6 +1889,24 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get libraryFilterFormat => '形式';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1898,6 +1916,18 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_ko.dart

@@ -1882,6 +1882,24 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1891,6 +1909,18 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_nl.dart

@@ -1902,6 +1902,24 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1911,6 +1929,18 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_pt.dart

@@ -1902,6 +1902,24 @@ class AppLocalizationsPt extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1911,6 +1929,18 @@ class AppLocalizationsPt extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_ru.dart

@@ -1948,6 +1948,24 @@ class AppLocalizationsRu extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Формат';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Сортировка';
 
@@ -1957,6 +1975,18 @@ class AppLocalizationsRu extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Старые';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Только что';
 

lib/l10n/app_localizations_tr.dart

@@ -1908,6 +1908,24 @@ class AppLocalizationsTr extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1917,6 +1935,18 @@ class AppLocalizationsTr extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/app_localizations_zh.dart

@@ -1902,6 +1902,24 @@ class AppLocalizationsZh extends AppLocalizations {
   @override
   String get libraryFilterFormat => 'Format';
 
+  @override
+  String get libraryFilterMetadata => 'Metadata';
+
+  @override
+  String get libraryFilterMetadataComplete => 'Complete metadata';
+
+  @override
+  String get libraryFilterMetadataMissingAny => 'Missing any metadata';
+
+  @override
+  String get libraryFilterMetadataMissingYear => 'Missing year';
+
+  @override
+  String get libraryFilterMetadataMissingGenre => 'Missing genre';
+
+  @override
+  String get libraryFilterMetadataMissingAlbumArtist => 'Missing album artist';
+
   @override
   String get libraryFilterSort => 'Sort';
 
@@ -1911,6 +1929,18 @@ class AppLocalizationsZh extends AppLocalizations {
   @override
   String get libraryFilterSortOldest => 'Oldest';
 
+  @override
+  String get libraryFilterSortAlbumAsc => 'Album (A-Z)';
+
+  @override
+  String get libraryFilterSortAlbumDesc => 'Album (Z-A)';
+
+  @override
+  String get libraryFilterSortGenreAsc => 'Genre (A-Z)';
+
+  @override
+  String get libraryFilterSortGenreDesc => 'Genre (Z-A)';
+
   @override
   String get timeJustNow => 'Just now';
 

lib/l10n/arb/app_en.arb

@@ -2513,6 +2513,30 @@
   "@libraryFilterFormat": {
     "description": "Filter section - file format"
   },
+  "libraryFilterMetadata": "Metadata",
+  "@libraryFilterMetadata": {
+    "description": "Filter section - metadata completeness"
+  },
+  "libraryFilterMetadataComplete": "Complete metadata",
+  "@libraryFilterMetadataComplete": {
+    "description": "Filter option - items with complete metadata"
+  },
+  "libraryFilterMetadataMissingAny": "Missing any metadata",
+  "@libraryFilterMetadataMissingAny": {
+    "description": "Filter option - items missing any tracked metadata field"
+  },
+  "libraryFilterMetadataMissingYear": "Missing year",
+  "@libraryFilterMetadataMissingYear": {
+    "description": "Filter option - items missing release year/date"
+  },
+  "libraryFilterMetadataMissingGenre": "Missing genre",
+  "@libraryFilterMetadataMissingGenre": {
+    "description": "Filter option - items missing genre"
+  },
+  "libraryFilterMetadataMissingAlbumArtist": "Missing album artist",
+  "@libraryFilterMetadataMissingAlbumArtist": {
+    "description": "Filter option - items missing album artist"
+  },
   "libraryFilterSort": "Sort",
   "@libraryFilterSort": {
     "description": "Filter section - sort order"
@@ -2525,6 +2549,22 @@
   "@libraryFilterSortOldest": {
     "description": "Sort option - oldest first"
   },
+  "libraryFilterSortAlbumAsc": "Album (A-Z)",
+  "@libraryFilterSortAlbumAsc": {
+    "description": "Sort option - album ascending"
+  },
+  "libraryFilterSortAlbumDesc": "Album (Z-A)",
+  "@libraryFilterSortAlbumDesc": {
+    "description": "Sort option - album descending"
+  },
+  "libraryFilterSortGenreAsc": "Genre (A-Z)",
+  "@libraryFilterSortGenreAsc": {
+    "description": "Sort option - genre ascending"
+  },
+  "libraryFilterSortGenreDesc": "Genre (Z-A)",
+  "@libraryFilterSortGenreDesc": {
+    "description": "Sort option - genre descending"
+  },
   "timeJustNow": "Just now",
   "@timeJustNow": {
     "description": "Relative time - less than a minute ago"