refactor: remove PdfMetadata/PdfAMetadata, use result DTOs directly

PdfMetadata and PdfAMetadata were redundant intermediate classes that
mirrored PdfValidationResult and PdfAValidationResult exactly.

Changes:
- Delete PdfMetadata.cs and PdfAMetadata.cs
- IPdfProcessor.ValidateAsync now returns PdfValidationResult directly
- IPdfProcessor.ValidatePdfAAsync now returns PdfAValidationResult directly
- ValidatePdfQueryHandler: remove IMapper dependency, return result directly
- ValidatePdfAQueryHandler: remove IMapper dependency, return result directly
- MappingProfile: remove the two now-obsolete CreateMap calls
- PdfValidationResult: add IsEncrypted parameter (was missing)

DocumentOperator.Application/ValidatePdfA/Queries/ValidatePdfAQuery.cs

@@ -1,4 +1,3 @@
-using AutoMapper;
 using DocumentService.Application.Common.DTOs;
 using DocumentService.Application.Common.Interfaces;
 using MediatR;
@@ -18,20 +17,12 @@ public record ValidatePdfAQuery : IRequest<PdfAValidationResult>
 
 /// <summary>
 /// Handler for ValidatePdfAQuery
-/// Orchestrates PDF/A validation using IPdfProcessor and AutoMapper
 /// </summary>
-public class ValidatePdfAQueryHandler(IPdfProcessor PdfProcessor, IMapper Mapper) 
+public class ValidatePdfAQueryHandler(IPdfProcessor pdfProcessor) 
     : IRequestHandler<ValidatePdfAQuery, PdfAValidationResult>
 {
-    /// <summary>
-    /// Validates PDF/A and returns metadata with conformance level
-    /// </summary>
     public async Task<PdfAValidationResult> Handle(ValidatePdfAQuery request, CancellationToken cancellationToken)
     {
-        // Call DevExpress service directly with stream (exceptions propagate naturally)
-        var metadata = await PdfProcessor.ValidatePdfAAsync(request.PdfStream);
-
-        // Map DTO to response DTO using AutoMapper
-        return Mapper.Map<PdfAValidationResult>(metadata);
+        return await pdfProcessor.ValidatePdfAAsync(request.PdfStream);
     }
 }