refactor: Update Application handlers to convert byte[] to Stream

- ValidatePdfQueryHandler: Convert byte[] → MemoryStream before calling IPdfProcessor
- ValidatePdfAQueryHandler: Same pattern
- Update AutoMapper namespace imports (remove Domain.Models.ValueObjects references)

DocumentOperator.Application/Common/Mapping/MappingProfile.cs

@@ -43,5 +43,12 @@ public class MappingProfile : Profile
         CreateMap<AlternativeScheme, AlternativeSchemeDto>()
             .ForMember(dest => dest.Name, opt => opt.MapFrom(src => src.Name ?? string.Empty))
             .ForMember(dest => dest.Instruction, opt => opt.MapFrom(src => src.Instruction ?? string.Empty));
+
+        // AttachmentInfo -> AttachmentCheckResult
+        CreateMap<AttachmentInfo, AttachmentCheckResult>();
+
+        // AttachmentMetadata -> AttachmentDto
+        CreateMap<AttachmentMetadata, AttachmentDto>()
+            .ForMember(dest => dest.Size, opt => opt.MapFrom(src => src.SizeBytes));
     }
 }