feat(backend): add source, external id and artist to tracks

backend/Musify.Domain/Entities/Track.cs

@@ -23,6 +23,17 @@ namespace Musify.Domain.Entities
         [Required]
         public int Duration { get; set; }
 
+        [Required]
+        [MaxLength(200)]
+        public string Artist { get; set; } = string.Empty;
+
+        [Required]
+        public TrackSource Source { get; set; } = TrackSource.Local;
+
+        [Required]
+        [MaxLength(16)]
+        public string ExternalId { get; set; } = string.Empty;
+
         [Required]
         [MaxLength(64)]
         public required string OriginalPictureName { get; set; }

backend/Musify.Domain/ValueObjects/TrackSource.cs

@@ -0,0 +1,8 @@
+namespace Musify.Domain.ValueObjects
+{
+    public enum TrackSource
+    {
+        Local = 0,
+        YouTube = 1
+    }
+}