refactor: remove Qobuz from built-in provider registry, add retired provider detection

Empty the builtInProviderRegistry now that all built-in providers are
retired. Introduce isRetiredBuiltInDownloadProvider and
isRetiredBuiltInMetadataProvider to classify deezer/qobuz/tidal/spotify
as retired, replacing ad-hoc string checks. Add Dart-side metadata
provider priority reconciliation that replaces retired providers with
extensions declaring replacesBuiltInProviders. Remove getQobuzMetadata
from native bridges and platform_bridge.dart. Update crowdin.yml with
additional locale mappings.

lib/providers/extension_provider.dart

@@ -758,6 +758,7 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
       state = state.copyWith(extensions: extensions);
       await _reconcileDownloadProviderPriority();
       await _reconcileDefaultDownloadService();
+      await _reconcileMetadataProviderPriority();
       _reconcileSearchProvider();
       _log.d('Loaded ${extensions.length} extensions');
 
@@ -866,6 +867,7 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
       state = state.copyWith(extensions: extensions);
       await _reconcileDownloadProviderPriority();
       await _reconcileDefaultDownloadService();
+      await _reconcileMetadataProviderPriority();
       _reconcileSearchProvider();
 
       if (!enabled && ext != null) {
@@ -914,6 +916,28 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
     _log.d('Reconciled provider priority after extension update: $sanitized');
   }
 
+  Future<void> _reconcileMetadataProviderPriority() async {
+    if (state.metadataProviderPriority.isEmpty) {
+      return;
+    }
+
+    final replaced = _replaceRetiredBuiltInMetadataProviders(
+      state.metadataProviderPriority,
+    );
+    final sanitized = _sanitizeMetadataProviderPriority(replaced);
+    if (jsonEncode(sanitized) == jsonEncode(state.metadataProviderPriority)) {
+      return;
+    }
+
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setString(_metadataProviderPriorityKey, jsonEncode(sanitized));
+    await PlatformBridge.setMetadataProviderPriority(sanitized);
+    state = state.copyWith(metadataProviderPriority: sanitized);
+    _log.d(
+      'Reconciled metadata provider priority after extension update: $sanitized',
+    );
+  }
+
   String? _firstEnabledExtensionDownloadProviderId() {
     return state.extensions
         .where((ext) => ext.enabled && ext.hasDownloadProvider)
@@ -951,6 +975,21 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
         .firstOrNull;
   }
 
+  String? replacedBuiltInMetadataProviderFor(String providerId) {
+    final normalized = providerId.trim().toLowerCase();
+    if (normalized.isEmpty) return null;
+
+    return state.extensions
+        .where(
+          (ext) =>
+              ext.enabled &&
+              ext.hasMetadataProvider &&
+              ext.replacesBuiltInProviders.contains(normalized),
+        )
+        .map((ext) => ext.id)
+        .firstOrNull;
+  }
+
   bool downloadProviderMatchesBuiltIn(
     String providerId,
     String builtInProviderId,
@@ -1204,7 +1243,9 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
       if (savedJson != null) {
         final saved = jsonDecode(savedJson) as List<dynamic>;
         priority = _sanitizeMetadataProviderPriority(
-          saved.map((e) => e as String).toList(),
+          _replaceRetiredBuiltInMetadataProviders(
+            saved.map((e) => e as String).toList(),
+          ),
         );
         _log.d('Loaded metadata provider priority from prefs: $priority');
         await prefs.setString(
@@ -1233,7 +1274,9 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
   Future<void> setMetadataProviderPriority(List<String> priority) async {
     try {
       final prefs = await SharedPreferences.getInstance();
-      final sanitized = _sanitizeMetadataProviderPriority(priority);
+      final sanitized = _sanitizeMetadataProviderPriority(
+        _replaceRetiredBuiltInMetadataProviders(priority),
+      );
       await prefs.setString(
         _metadataProviderPriorityKey,
         jsonEncode(sanitized),
@@ -1294,6 +1337,18 @@ class ExtensionNotifier extends Notifier<ExtensionState> {
     ];
   }
 
+  List<String> _replaceRetiredBuiltInMetadataProviders(List<String> input) {
+    final result = <String>[];
+    for (final provider in input) {
+      final replacement = replacedBuiltInMetadataProviderFor(provider);
+      final resolved = replacement ?? provider;
+      if (!result.contains(resolved)) {
+        result.add(resolved);
+      }
+    }
+    return result;
+  }
+
   List<String> _sanitizeMetadataProviderPriority(List<String> input) {
     final allowed = getAllMetadataProviders().toSet();
     final preferredOrder = getAllMetadataProviders();

lib/services/platform_bridge.dart

@@ -524,22 +524,6 @@ class PlatformBridge {
     return jsonDecode(result as String) as Map<String, dynamic>;
   }
 
-  static Future<Map<String, dynamic>> getQobuzMetadata(
-    String resourceType,
-    String resourceId,
-  ) async {
-    final result = await _channel.invokeMethod('getQobuzMetadata', {
-      'resource_type': resourceType,
-      'resource_id': resourceId,
-    });
-    if (result == null) {
-      throw Exception(
-        'getQobuzMetadata returned null for $resourceType:$resourceId',
-      );
-    }
-    return jsonDecode(result as String) as Map<String, dynamic>;
-  }
-
   static Future<Map<String, dynamic>> parseProviderUrl(String url) async {
     final result = await _channel.invokeMethod('parseProviderUrl', {
       'url': url,