feat(extensions): route Deezer metadata through enabled extension

Prefer the enabled Deezer metadata extension over the built-in provider
when resolving album, track, and playlist metadata requests.

go_backend/exports.go

@@ -2281,6 +2281,16 @@ func GetProviderMetadataJSON(providerID, resourceType, resourceID string) (strin
 
 	switch strings.ToLower(trimmedProviderID) {
 	case "deezer":
+		if response, ok, err := getEnabledExtensionProviderMetadataResponse(trimmedProviderID, resourceType, resourceID); ok || err != nil {
+			if err != nil {
+				return "", err
+			}
+			jsonBytes, err := json.Marshal(response)
+			if err != nil {
+				return "", err
+			}
+			return string(jsonBytes), nil
+		}
 		return GetDeezerMetadata(resourceType, resourceID)
 	default:
 		response, err := getExtensionProviderMetadataResponse(trimmedProviderID, resourceType, resourceID)
@@ -2296,6 +2306,19 @@ func GetProviderMetadataJSON(providerID, resourceType, resourceID string) (strin
 	}
 }
 
+func getEnabledExtensionProviderMetadataResponse(providerID, resourceType, resourceID string) (map[string]interface{}, bool, error) {
+	manager := getExtensionManager()
+	ext, err := manager.GetExtension(providerID)
+	if err != nil || ext == nil || !ext.Enabled || !ext.Manifest.IsMetadataProvider() {
+		return nil, false, nil
+	}
+	response, err := getExtensionProviderMetadataResponse(providerID, resourceType, resourceID)
+	if err != nil {
+		return nil, true, err
+	}
+	return response, true, nil
+}
+
 func GetDeezerExtendedMetadata(trackID string) (string, error) {
 	if trackID == "" {
 		return "", fmt.Errorf("empty track ID")

go_backend/exports_supplement_test.go

@@ -44,6 +44,31 @@ func TestDownloadErrorClassificationDetectsVerificationRequired(t *testing.T) {
 	}
 }
 
+func TestGetProviderMetadataPrefersEnabledDeezerExtension(t *testing.T) {
+	dir := t.TempDir()
+	if err := InitExtensionSystem(filepath.Join(dir, "extensions"), filepath.Join(dir, "data")); err != nil {
+		t.Fatalf("InitExtensionSystem: %v", err)
+	}
+	CleanupExtensions()
+	defer CleanupExtensions()
+
+	ext := newTestLoadedExtension(t, ExtensionTypeMetadataProvider)
+	ext.ID = "deezer"
+	ext.Manifest.Name = "deezer"
+	manager := getExtensionManager()
+	manager.mu.Lock()
+	manager.extensions = map[string]*loadedExtension{ext.ID: ext}
+	manager.mu.Unlock()
+
+	jsonText, err := GetProviderMetadataJSON("deezer", "album", "201")
+	if err != nil {
+		t.Fatalf("GetProviderMetadataJSON deezer album: %v", err)
+	}
+	if !strings.Contains(jsonText, "album-track") {
+		t.Fatalf("expected enabled deezer extension metadata, got %s", jsonText)
+	}
+}
+
 func TestExportsJSONWrappersAndExtensionManagerSurface(t *testing.T) {
 	dir := t.TempDir()
 	dataDir := filepath.Join(dir, "data")