Add DeleteOutResCommandValidator for input validation

Introduce DeleteOutResCommandValidator using FluentValidation
to enforce business rules for the DeleteOutResCommand. Added
a validation rule to ensure at least one of ActionId or
ProfileId is provided, with a descriptive error message if
neither is present. Included necessary using directives for
FluentValidation and the relevant namespace.

src/ReC.Application/OutResults/Commands/DeleteOutResCommandValidator.cs

@@ -0,0 +1,14 @@
+using FluentValidation;
+
+namespace ReC.Application.OutResults.Commands;
+
+public class DeleteOutResCommandValidator : AbstractValidator<DeleteOutResCommand>
+{
+    public DeleteOutResCommandValidator()
+    {
+        RuleFor(x => x)
+            .Must(x => x.ActionId.HasValue || x.ProfileId.HasValue)
+            .WithMessage("At least one of ActionId or ProfileId must be provided.")
+            .WithName("Identifier");
+    }
+}