feat(app): implement RefreshCommand handler with token rotation and chain revocation

src/api/SIGCM2.Application/Auth/Refresh/RefreshCommandValidator.cs

@@ -0,0 +1,16 @@
+using FluentValidation;
+
+namespace SIGCM2.Application.Auth.Refresh;
+
+public sealed class RefreshCommandValidator : AbstractValidator<RefreshCommand>
+{
+    public RefreshCommandValidator()
+    {
+        RuleFor(x => x.AccessToken)
+            .NotEmpty().WithMessage("accessToken is required");
+
+        RuleFor(x => x.RefreshToken)
+            .NotEmpty().WithMessage("refreshToken is required")
+            .MinimumLength(20).WithMessage("refreshToken must be at least 20 characters");
+    }
+}