feat: wip on testing login flows

src/FiscalOS.API/Identity/User.cs

@@ -3,4 +3,7 @@ namespace FiscalOS.API.Identity;
 internal sealed class User
 {
   public Guid Id { get; init; }
+  public string Username { get; init; } = string.Empty;
+
+  public ICollection<RefreshToken> RefreshTokens { get; init; } = [];
 }