feat: Implement a customizable dashboard with user preferences and a dynamic widget system.

src/backend/Zentral.Domain/Entities/UserDashboardPreference.cs

@@ -0,0 +1,8 @@
+namespace Zentral.Domain.Entities;
+
+public class UserDashboardPreference : BaseEntity
+{
+    public int UtenteId { get; set; }
+    public Utente? Utente { get; set; }
+    public string LayoutJson { get; set; } = string.Empty;
+}