Clean up domain entities: shared picture value object, lifecycle and ownership interfaces, explicit tables

backend/Core/Musify.Domain/Abstractions/IHasLifeCycle.cs

@@ -0,0 +1,10 @@
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Domain.Abstractions;
+
+public interface IHasLifeCycle
+{
+    public Guid Id { get; }
+
+    public LifeCycleStatus LifeCycleStatus { get; set; }
+}

backend/Core/Musify.Domain/Abstractions/IOwnedEntity.cs

@@ -0,0 +1,8 @@
+namespace Musify.Domain.Abstractions;
+
+public interface IOwnedEntity
+{
+    public Guid Id { get; }
+
+    public long OwnerUserId { get; }
+}