Update README, remove STREAM_API_DESIGN, adjust solution

Enhanced README with German translation and examples.

- Added German translation to README alongside English content.
- Expanded installation, configuration, and usage examples.
- Documented static `Client` entry point and error handling.
- Removed STREAM_API_DESIGN.md as it is no longer relevant.
- Changed solution configuration to build in Release mode by default.

DocumentOperator.Application/Common/DTOs/PdfAMetadata.cs

@@ -1,34 +0,0 @@
-namespace DocumentService.Application.Common.DTOs;
-
-/// <summary>
-/// PDF/A validation metadata including conformance level and validation errors/warnings
-/// </summary>
-public sealed class PdfAMetadata(
-    bool isValid,
-    string pdfVersion,
-    int pageCount,
-    long fileSizeBytes,
-    bool encrypted,
-    string? pdfaVersion,
-    bool pdfaCompliant,
-    IReadOnlyList<string> errors,
-    IReadOnlyList<string> warnings)
-{
-    public bool IsValid { get; } = isValid;
-    public string PdfVersion { get; } = pdfVersion;
-    public int PageCount { get; } = pageCount;
-    public long FileSizeBytes { get; } = fileSizeBytes;
-    public bool Encrypted { get; } = encrypted;
-    public string? PdfAVersion { get; } = pdfaVersion;
-    public bool PdfACompliant { get; } = pdfaCompliant;
-    public IReadOnlyList<string> Errors { get; } = errors;
-    public IReadOnlyList<string> Warnings { get; } = warnings;
-
-    // Computed property
-    public double FileSizeMB => FileSizeBytes / 1024.0 / 1024.0;
-
-    public override string ToString()
-    {
-        return $"PDF/A: {PdfAVersion ?? "None"}, {PageCount} pages, {FileSizeMB:F2} MB, Compliant: {PdfACompliant}";
-    }
-}

DocumentOperator.Application/Common/DTOs/PdfMetadata.cs

@@ -1,23 +0,0 @@
-namespace DocumentService.Application.Common.DTOs;
-
-public sealed class PdfMetadata(
-    int pageCount,
-    long fileSizeBytes,
-    string pdfVersion,
-    bool hasAttachments,
-    int attachmentCount)
-{
-    public int PageCount { get; } = pageCount;
-    public long FileSizeBytes { get; } = fileSizeBytes;
-    public string PdfVersion { get; } = pdfVersion;
-    public bool HasAttachments { get; } = hasAttachments;
-    public int AttachmentCount { get; } = attachmentCount;
-
-    // Computed Property (berechnet aus FileSizeBytes)
-    public double FileSizeMB => FileSizeBytes / 1024.0 / 1024.0;
-
-    public override string ToString()
-    {
-        return $"PDF: {PageCount} pages, {FileSizeMB:F2} MB, Version {PdfVersion}, Attachments: {AttachmentCount}";
-    }
-}

DocumentOperator.Application/DocumentService.Application.csproj

@@ -1,36 +0,0 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
-    <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <Compile Remove="DependencyInjection\**" />
-    <Compile Remove="Features\**" />
-    <EmbeddedResource Remove="DependencyInjection\**" />
-    <EmbeddedResource Remove="Features\**" />
-    <None Remove="DependencyInjection\**" />
-    <None Remove="Features\**" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <PackageReference Include="AutoMapper" Version="16.2.0" />
-    <PackageReference Include="Codecrete.SwissQRBill.Generator" Version="3.4.0" />
-    <PackageReference Include="FluentValidation" Version="12.1.1" />
-    <PackageReference Include="FluentValidation.DependencyInjectionExtensions" Version="12.1.1" />
-    <PackageReference Include="MediatR" Version="14.1.0" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.10" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="10.0.10" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <ProjectReference Include="..\DocumentOperator.Domain\DocumentService.Domain.csproj" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Folder Include="Common\Mappings\" />
-  </ItemGroup>
-
-</Project>

DocumentOperator.Tests/Unit/Application/Features/ValidatePdf/ValidatePdfHandlerTests.cs

@@ -1,91 +0,0 @@
-using AutoMapper;
-using DocumentService.Application.Common.DTOs;
-using DocumentService.Application.Common.Interfaces;
-using DocumentService.Application.ValidatePdf.Queries;
-using DocumentService.Domain.Common.Exceptions;
-using FluentAssertions;
-using Moq;
-using Xunit;
-
-namespace DocumentService.Tests.Unit.Application.Features.ValidatePdf;
-
-public class ValidatePdfHandlerTests
-{
-    private readonly Mock<IPdfProcessor> _mockPdfProcessor;
-    private readonly Mock<IMapper> _mockMapper;
-    private readonly ValidatePdfQueryHandler _handler;
-
-    public ValidatePdfHandlerTests()
-    {
-        _mockPdfProcessor = new Mock<IPdfProcessor>();
-        _mockMapper = new Mock<IMapper>();
-        _handler = new ValidatePdfQueryHandler(_mockPdfProcessor.Object, _mockMapper.Object);
-    }
-
-    [Fact]
-    public async Task Handle_ValidPdf_ReturnsPdfMetadata()
-    {
-        // Arrange
-        var pdfBytes = "%PDF"u8.ToArray(); // "%PDF"
-        var query = new ValidatePdfQuery { PdfStream = new MemoryStream(pdfBytes) };
-
-        var domainMetadata = new PdfMetadata(
-            pageCount: 5,
-            fileSizeBytes: 1024,
-            pdfVersion: "1.4",
-            hasAttachments: false,
-            attachmentCount: 0
-        );
-
-        var expectedDto = new PdfValidationResult(
-            PageCount: 5,
-            FileSizeBytes: 1024,
-            FileSizeMB: 0.00,
-            PdfVersion: "1.4",
-            HasAttachments: false,
-            AttachmentCount: 0
-        );
-
-        _mockPdfProcessor
-            .Setup(x => x.ValidateAsync(It.IsAny<Stream>()))
-            .ReturnsAsync(domainMetadata);
-
-        _mockMapper
-            .Setup(x => x.Map<PdfValidationResult>(domainMetadata))
-            .Returns(expectedDto);
-
-        // Act
-        var result = await _handler.Handle(query, CancellationToken.None);
-
-        // Assert
-        result.Should().NotBeNull();
-        result.PageCount.Should().Be(5);
-        result.FileSizeBytes.Should().Be(1024);
-        result.PdfVersion.Should().Be("1.4");
-        result.HasAttachments.Should().BeFalse();
-        result.AttachmentCount.Should().Be(0);
-
-        _mockPdfProcessor.Verify(x => x.ValidateAsync(It.IsAny<Stream>()), Times.Once);
-        _mockMapper.Verify(x => x.Map<PdfValidationResult>(domainMetadata), Times.Once);
-    }
-
-    [Fact]
-    public async Task Handle_PdfProcessorThrowsException_PropagatesException()
-    {
-        // Arrange
-        var pdfBytes = "%PDF"u8.ToArray(); // "%PDF"
-        var query = new ValidatePdfQuery { PdfStream = new MemoryStream(pdfBytes) };
-
-        _mockPdfProcessor
-            .Setup(x => x.ValidateAsync(It.IsAny<Stream>()))
-            .ThrowsAsync(new BadRequestException("Invalid PDF format"));
-
-        // Act & Assert
-        var exception = await Assert.ThrowsAsync<BadRequestException>(
-            () => _handler.Handle(query, CancellationToken.None)
-        );
-
-        exception.Message.Should().Be("Invalid PDF format");
-        _mockPdfProcessor.Verify(x => x.ValidateAsync(It.IsAny<Stream>()), Times.Once);
-    }
-}

DocumentOperator.Tests/Unit/Application/Features/ValidatePdfA/ValidatePdfAQueryHandlerTests.cs

@@ -1,214 +0,0 @@
-using AutoMapper;
-using DocumentService.Application.Common.DTOs;
-using DocumentService.Application.Common.Interfaces;
-using DocumentService.Application.ValidatePdfA.Queries;
-using DocumentService.Domain.Common.Exceptions;
-
-using FluentAssertions;
-using Moq;
-using Xunit;
-
-namespace DocumentService.Tests.Unit.Application.Features.ValidatePdfA;
-
-public class ValidatePdfAQueryHandlerTests
-{
-    private readonly Mock<IPdfProcessor> _mockPdfProcessor;
-    private readonly Mock<IMapper> _mockMapper;
-    private readonly ValidatePdfAQueryHandler _handler;
-
-    public ValidatePdfAQueryHandlerTests()
-    {
-        _mockPdfProcessor = new Mock<IPdfProcessor>();
-        _mockMapper = new Mock<IMapper>();
-        _handler = new ValidatePdfAQueryHandler(_mockPdfProcessor.Object, _mockMapper.Object);
-    }
-
-    [Fact]
-    public async Task Handle_ValidPdfA_ReturnsPdfAMetadata()
-    {
-        // Arrange
-        var pdfBytes = "%PDF"u8.ToArray(); // "%PDF"
-        var query = new ValidatePdfAQuery { PdfStream = new MemoryStream(pdfBytes) };
-
-        var domainMetadata = new PdfAMetadata(
-            isValid: true,
-            pdfVersion: "1.7",
-            pageCount: 3,
-            fileSizeBytes: 2048,
-            encrypted: false,
-            pdfaVersion: "PDF/A-3b",
-            pdfaCompliant: true,
-            errors: [],
-            warnings: []
-        );
-
-        var expectedDto = new PdfAValidationResult
-        {
-            IsValid = true,
-            PdfVersion = "1.7",
-            PageCount = 3,
-            FileSize = 2048,
-            Encrypted = false,
-            PdfAVersion = "PDF/A-3b",
-            PdfACompliant = true,
-            Errors = new List<string>(),
-            Warnings = new List<string>()
-        };
-
-        _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
-            .ReturnsAsync(domainMetadata);
-
-        _mockMapper
-            .Setup(x => x.Map<PdfAValidationResult>(domainMetadata))
-            .Returns(expectedDto);
-
-        // Act
-        var result = await _handler.Handle(query, CancellationToken.None);
-
-        // Assert
-        result.Should().NotBeNull();
-        result.IsValid.Should().BeTrue();
-        result.PageCount.Should().Be(3);
-        result.PdfVersion.Should().Be("1.7");
-        result.PdfAVersion.Should().Be("PDF/A-3b");
-        result.PdfACompliant.Should().BeTrue();
-        result.Encrypted.Should().BeFalse();
-        result.Errors.Should().BeEmpty();
-        result.Warnings.Should().BeEmpty();
-
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
-        _mockMapper.Verify(x => x.Map<PdfAValidationResult>(domainMetadata), Times.Once);
-    }
-
-    [Fact]
-    public async Task Handle_NonCompliantPdfA_ReturnsErrorsAndWarnings()
-    {
-        // Arrange
-        var pdfBytes = new byte[] { 0x25, 0x50, 0x44, 0x46 }; // "%PDF"
-        var query = new ValidatePdfAQuery { PdfStream = new MemoryStream(pdfBytes) };
-
-        var errors = new List<string> { "Missing XMP metadata", "Invalid color space" };
-        var warnings = new List<string> { "Embedded font not subset" };
-
-        var domainMetadata = new PdfAMetadata(
-            isValid: false,
-            pdfVersion: "1.4",
-            pageCount: 2,
-            fileSizeBytes: 1024,
-            encrypted: false,
-            pdfaVersion: null,
-            pdfaCompliant: false,
-            errors: errors,
-            warnings: warnings
-        );
-
-        var expectedDto = new PdfAValidationResult
-        {
-            IsValid = false,
-            PdfVersion = "1.4",
-            PageCount = 2,
-            FileSize = 1024,
-            Encrypted = false,
-            PdfAVersion = null,
-            PdfACompliant = false,
-            Errors = errors,
-            Warnings = warnings
-        };
-
-        _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
-            .ReturnsAsync(domainMetadata);
-
-        _mockMapper
-            .Setup(x => x.Map<PdfAValidationResult>(domainMetadata))
-            .Returns(expectedDto);
-
-        // Act
-        var result = await _handler.Handle(query, CancellationToken.None);
-
-        // Assert
-        result.Should().NotBeNull();
-        result.IsValid.Should().BeFalse();
-        result.PdfACompliant.Should().BeFalse();
-        result.PdfAVersion.Should().BeNull();
-        result.Errors.Should().HaveCount(2);
-        result.Errors.Should().Contain("Missing XMP metadata");
-        result.Warnings.Should().HaveCount(1);
-
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
-    }
-
-    [Fact]
-    public async Task Handle_EncryptedPdf_ReturnsEncryptedFlag()
-    {
-        // Arrange
-        var pdfBytes = new byte[] { 0x25, 0x50, 0x44, 0x46 }; // "%PDF"
-        var query = new ValidatePdfAQuery { PdfStream = new MemoryStream(pdfBytes) };
-
-        var domainMetadata = new PdfAMetadata(
-            isValid: true,
-            pdfVersion: "1.7",
-            pageCount: 1,
-            fileSizeBytes: 512,
-            encrypted: true,
-            pdfaVersion: null,
-            pdfaCompliant: false,
-            errors: new List<string> { "Encrypted PDFs cannot be PDF/A compliant" },
-            warnings: new List<string>()
-        );
-
-        var expectedDto = new PdfAValidationResult
-        {
-            IsValid = true,
-            PdfVersion = "1.7",
-            PageCount = 1,
-            FileSize = 512,
-            Encrypted = true,
-            PdfAVersion = null,
-            PdfACompliant = false,
-            Errors = new List<string> { "Encrypted PDFs cannot be PDF/A compliant" },
-            Warnings = new List<string>()
-        };
-
-        _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
-            .ReturnsAsync(domainMetadata);
-
-        _mockMapper
-            .Setup(x => x.Map<PdfAValidationResult>(domainMetadata))
-            .Returns(expectedDto);
-
-        // Act
-        var result = await _handler.Handle(query, CancellationToken.None);
-
-        // Assert
-        result.Should().NotBeNull();
-        result.Encrypted.Should().BeTrue();
-        result.PdfACompliant.Should().BeFalse();
-        result.Errors.Should().Contain("Encrypted PDFs cannot be PDF/A compliant");
-
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
-    }
-
-    [Fact]
-    public async Task Handle_PdfProcessorThrowsException_PropagatesException()
-    {
-        // Arrange
-        var pdfBytes = new byte[] { 0x25, 0x50, 0x44, 0x46 }; // "%PDF"
-        var query = new ValidatePdfAQuery { PdfStream = new MemoryStream(pdfBytes) };
-
-        _mockPdfProcessor
-            .Setup(x => x.ValidatePdfAAsync(It.IsAny<Stream>()))
-            .ThrowsAsync(new BadRequestException("Invalid PDF format"));
-
-        // Act & Assert
-        var exception = await Assert.ThrowsAsync<BadRequestException>(
-            () => _handler.Handle(query, CancellationToken.None)
-        );
-
-        exception.Message.Should().Be("Invalid PDF format");
-        _mockPdfProcessor.Verify(x => x.ValidatePdfAAsync(It.IsAny<Stream>()), Times.Once);
-    }
-}
-

DocumentOperator.Tests/Unit/Client/PdfValidationClientTests.cs

@@ -1,168 +0,0 @@
-using DocumentService.Client.Clients;
-using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
-using FluentAssertions;
-using Microsoft.Extensions.Logging.Abstractions;
-using System.Net;
-using System.Net.Http;
-using System.Text.Json;
-
-namespace DocumentService.Tests.Unit.Client;
-
-/// <summary>
-/// Unit tests for <see cref="PdfValidationClient"/>.
-/// All tests use a fake <see cref="MockHttpMessageHandler"/> — no real HTTP calls are made.
-/// </summary>
-public class PdfValidationClientTests
-{
-    // ?? helpers ?????????????????????????????????????????????????????????????
-
-    private static (PdfValidationClient client, MockHttpMessageHandler handler) Build<T>(T responseBody)
-    {
-        var handler = MockHttpMessageHandler.ReturningJson(responseBody);
-        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
-        var client = new PdfValidationClient(httpClient, NullLogger<PdfValidationClient>.Instance);
-        return (client, handler);
-    }
-
-    private static byte[] FakePdfBytes() => "fake-pdf-content"u8.ToArray();
-
-    // ?? ValidatePdfAsync (Stream) ????????????????????????????????????????????
-
-    [Fact]
-    public async Task ValidatePdfAsync_Stream_SendsMultipartPost()
-    {
-        // Arrange
-        var expected = new PdfValidationResult { PageCount = 3, PdfVersion = "1.7", FileSizeBytes = 2048 };
-        var (client, handler) = Build(expected);
-
-        // Act
-        var result = await client.ValidatePdfAsync(new MemoryStream(FakePdfBytes()));
-
-        // Assert
-        result.PageCount.Should().Be(3);
-        result.PdfVersion.Should().Be("1.7");
-        handler.LastRequest!.Method.Should().Be(HttpMethod.Post);
-        handler.LastRequest.RequestUri!.PathAndQuery.Should().Be("/api/pdf/validation/validate");
-        handler.LastRequest.Content.Should().BeOfType<MultipartFormDataContent>();
-    }
-
-    [Fact]
-    public async Task ValidatePdfAsync_Stream_ThrowsWhenApiReturnsNull()
-    {
-        // Arrange — API returns JSON null
-        var handler = MockHttpMessageHandler.ReturningJson<PdfValidationResult?>(null);
-        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
-        var client = new PdfValidationClient(httpClient, NullLogger<PdfValidationClient>.Instance);
-
-        // Act & Assert
-        await client.Invoking(c => c.ValidatePdfAsync(new MemoryStream(FakePdfBytes())))
-            .Should().ThrowAsync<InvalidOperationException>();
-    }
-
-    // ?? ValidatePdfAsync (byte[]) ????????????????????????????????????????????
-
-    [Fact]
-    public async Task ValidatePdfAsync_Bytes_SendsJsonWithBase64()
-    {
-        // Arrange
-        var expected = new PdfValidationResult { PageCount = 1, IsEncrypted = false };
-        var (client, handler) = Build(expected);
-
-        // Act
-        var result = await client.ValidatePdfAsync(FakePdfBytes());
-
-        // Assert
-        result.PageCount.Should().Be(1);
-        handler.LastRequest!.Content.Should().NotBeNull();
-        handler.LastRequest.Content!.Headers.ContentType!.MediaType.Should().Be("application/json");
-
-        var body = await handler.LastRequest.Content!.ReadAsStringAsync();
-        var doc = JsonDocument.Parse(body);
-        doc.RootElement.GetProperty("base64Pdf").GetString().Should().NotBeNullOrEmpty();
-    }
-
-    // ?? ValidatePdfAAsync (Stream) ???????????????????????????????????????????
-
-    [Fact]
-    public async Task ValidatePdfAAsync_Stream_SendsMultipartPost()
-    {
-        // Arrange
-        var expected = new PdfAValidationResult { IsValid = true, PdfAVersion = "PDF/A-3b", PageCount = 2 };
-        var (client, handler) = Build(expected);
-
-        // Act
-        var result = await client.ValidatePdfAAsync(new MemoryStream(FakePdfBytes()));
-
-        // Assert
-        result.IsValid.Should().BeTrue();
-        result.PdfAVersion.Should().Be("PDF/A-3b");
-        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/validation/validate-pdfa");
-        handler.LastRequest.Content.Should().BeOfType<MultipartFormDataContent>();
-    }
-
-    [Fact]
-    public async Task ValidatePdfAAsync_Stream_WithErrors_ReturnsErrors()
-    {
-        // Arrange
-        var expected = new PdfAValidationResult
-        {
-            IsValid = false,
-            Errors = new List<string> { "Missing embedded font", "Encryption not allowed" }
-        };
-        var (client, _) = Build(expected);
-
-        // Act
-        var result = await client.ValidatePdfAAsync(new MemoryStream(FakePdfBytes()));
-
-        // Assert
-        result.IsValid.Should().BeFalse();
-        result.Errors.Should().HaveCount(2).And.Contain("Missing embedded font");
-    }
-
-    // ?? ValidatePdfAAsync (byte[]) ???????????????????????????????????????????
-
-    [Fact]
-    public async Task ValidatePdfAAsync_Bytes_SendsJson()
-    {
-        // Arrange
-        var expected = new PdfAValidationResult { IsValid = true };
-        var (client, handler) = Build(expected);
-
-        // Act
-        await client.ValidatePdfAAsync(FakePdfBytes());
-
-        // Assert
-        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/validation/validate-pdfa");
-        handler.LastRequest.Content.Should().NotBeNull();
-        handler.LastRequest.Content!.Headers.ContentType!.MediaType.Should().Be("application/json");
-    }
-
-    // ?? HTTP error propagation ???????????????????????????????????????????????
-
-    [Fact]
-    public async Task ValidatePdfAsync_WhenApiReturns400_ThrowsHttpRequestException()
-    {
-        // Arrange
-        var handler = MockHttpMessageHandler.ReturningStatus(HttpStatusCode.BadRequest);
-        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
-        var client = new PdfValidationClient(httpClient, NullLogger<PdfValidationClient>.Instance);
-
-        // Act & Assert
-        await client.Invoking(c => c.ValidatePdfAsync(new MemoryStream(FakePdfBytes())))
-            .Should().ThrowAsync<HttpRequestException>();
-    }
-
-    [Fact]
-    public async Task ValidatePdfAsync_WhenApiReturns500_ThrowsHttpRequestException()
-    {
-        // Arrange
-        var handler = MockHttpMessageHandler.ReturningStatus(HttpStatusCode.InternalServerError);
-        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
-        var client = new PdfValidationClient(httpClient, NullLogger<PdfValidationClient>.Instance);
-
-        // Act & Assert
-        await client.Invoking(c => c.ValidatePdfAsync(new MemoryStream(FakePdfBytes())))
-            .Should().ThrowAsync<HttpRequestException>();
-    }
-}

DocumentService.API/Controllers/PdfAttachmentController.cs

@@ -2,7 +2,7 @@ using DocumentService.Application.AddAttachments;
 using DocumentService.Application.CheckPdfAttachments.Queries;
 using DocumentService.Application.Common.DTOs;
 using DocumentService.Application.ExtractPdfAttachments;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using DocumentService.Domain.Common.Exceptions;
 using MediatR;
 using Microsoft.AspNetCore.Http;
@@ -290,67 +290,3 @@ public class PdfAttachmentController(IMediator mediator) : ControllerBase
     }
 }
 
-/// <summary>
-/// Request DTO for Base64-encoded PDF attachment check
-/// </summary>
-public record CheckPdfAttachmentsRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public string Base64Pdf { get; init; } = string.Empty;
-}
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF attachment extraction
-/// </summary>
-public record ExtractPdfAttachmentsRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF with attachments to add
-/// </summary>
-public record AddAttachmentsRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-
-    /// <summary>
-    /// List of attachments to embed
-    /// </summary>
-    public required List<AttachmentRequestDto> Attachments { get; init; }
-}
-
-/// <summary>
-/// DTO for attachment file in request
-/// </summary>
-public record AttachmentRequestDto
-{
-    /// <summary>
-    /// File name (e.g., "invoice.xml", "document.pdf")
-    /// </summary>
-    /// <example>factur-x.xml</example>
-    public required string FileName { get; init; }
-
-    /// <summary>
-    /// File content encoded as Base64 string
-    /// </summary>
-    /// <example>PD94bWwgdmVyc2lvbj0iMS4wIj8+...</example>
-    public required string Base64Content { get; init; }
-
-    /// <summary>
-    /// MIME type (optional, e.g., "application/xml")
-    /// </summary>
-    /// <example>application/xml</example>
-    public string? MimeType { get; init; }
-}

DocumentService.API/Controllers/PdfConversionController.cs

@@ -1,6 +1,6 @@
 using DocumentService.Application.ConvertFromPdfA;
 using DocumentService.Application.ConvertToPdfA;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using DocumentService.Domain.Common.Exceptions;
 using MediatR;
 using Microsoft.AspNetCore.Http;

DocumentService.API/Controllers/PdfOperationsController.cs

@@ -1,5 +1,6 @@
 using DocumentService.Application.AddAnnotation;
 using DocumentService.Application.AddStamp;
+using DocumentService.Application.Common.DTOs.Requests;
 using DocumentService.Application.MergePdfs;
 using DocumentService.Domain.Common.Exceptions;
 using DocumentService.Domain.Models.ValueObjects;
@@ -158,7 +159,7 @@ public class PdfOperationsController(IMediator mediator) : ControllerBase
     [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
     [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status500InternalServerError)]
     public async Task<IActionResult> AnnotateFromBase64(
-        [FromBody] AddAnnotationBase64Command command,
+        [FromBody] AddAnnotationBase64Request command,
         CancellationToken cancellationToken)
     {
         // Convert Base64 to MemoryStream
@@ -404,116 +405,6 @@ public class AddAnnotationMultipartRequest
     public AnnotationOrigin Origin { get; set; } = AnnotationOrigin.BottomLeft;
 }
 
-/// <summary>
-/// Request DTO for Base64-encoded PDF merge operation (API layer only - converts to MergePdfsCommand)
-/// </summary>
-public record MergePdfsBase64Request
-{
-    /// <summary>
-    /// Array of Base64-encoded PDF files (minimum 2 required)
-    /// </summary>
-    /// <example>["JVBERi0xLjQK...", "JVBERi0xLjQK..."]</example>
-    public required List<string> Base64Pdfs { get; init; }
-
-    /// <summary>
-    /// Optional page ranges per PDF (null = all pages). 
-    /// Format: "1-3,5" means pages 1, 2, 3, and 5.
-    /// If provided, array length must match Base64Pdfs length.
-    /// </summary>
-    /// <example>["1-2", "1,3,5", null]</example>
-    public List<string?>? PageRanges { get; init; }
-}
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF annotation (API layer only - converts to AddAnnotationCommand)
-/// </summary>
-public record AddAnnotationBase64Command
-{
-    /// <summary>
-    /// Base64-encoded PDF file
-    /// </summary>
-    /// <example>"JVBERi0xLjQK..."</example>
-    public required string Base64Pdf { get; init; }
-
-    /// <summary>
-    /// Type of annotation to add
-    /// </summary>
-    /// <example>TextMarkup</example>
-    public required AnnotationType AnnotationType { get; init; }
-
-    /// <summary>
-    /// Target page number (1-indexed)
-    /// </summary>
-    /// <example>1</example>
-    public required int PageNumber { get; init; }
-
-    /// <summary>
-    /// Rectangle X1 coordinate (left)
-    /// </summary>
-    /// <example>100.0</example>
-    public required double X1 { get; init; }
-
-    /// <summary>
-    /// Rectangle Y1 coordinate (top or bottom depending on Origin)
-    /// </summary>
-    /// <example>100.0</example>
-    public required double Y1 { get; init; }
-
-    /// <summary>
-    /// Rectangle X2 coordinate (right). Optional if Width is provided.
-    /// </summary>
-    /// <example>200.0</example>
-    public double? X2 { get; init; }
-
-    /// <summary>
-    /// Rectangle Y2 coordinate (bottom or top depending on Origin). Optional if Height is provided.
-    /// </summary>
-    /// <example>120.0</example>
-    public double? Y2 { get; init; }
-
-    /// <summary>
-    /// Rectangle width. Alternative to X2 (X2 = X1 + Width). Optional if X2 is provided.
-    /// </summary>
-    /// <example>100.0</example>
-    public double? Width { get; init; }
-
-    /// <summary>
-    /// Rectangle height. Alternative to Y2 (Y2 = Y1 + Height). Optional if Y2 is provided.
-    /// </summary>
-    /// <example>20.0</example>
-    public double? Height { get; init; }
-
-    /// <summary>
-    /// Annotation content (required for FreeText and StickyNote)
-    /// </summary>
-    /// <example>"Important text to highlight"</example>
-    public string? Content { get; init; }
-
-    /// <summary>
-    /// Author name (optional)
-    /// </summary>
-    /// <example>"John Doe"</example>
-    public string? Author { get; init; }
-
-    /// <summary>
-    /// Hex color (6 digits, e.g., "FF0000" for red). Optional - defaults vary by annotation type.
-    /// </summary>
-    /// <example>"FFFF00"</example>
-    public string? Color { get; init; }
-
-    /// <summary>
-    /// Text markup style (Highlight, Underline, or Strikeout). Required for TextMarkup annotations.
-    /// </summary>
-    /// <example>Highlight</example>
-    public TextMarkupStyle? TextMarkupStyle { get; init; }
-
-    /// <summary>
-    /// Coordinate origin (BottomLeft = PDF native, TopLeft = UI-friendly). Default: BottomLeft
-    /// </summary>
-    /// <example>BottomLeft</example>
-    public AnnotationOrigin Origin { get; init; } = AnnotationOrigin.BottomLeft;
-}
-
 /// <summary>
 /// Request DTO for multipart/form-data stamp operation
 /// </summary>
@@ -618,111 +509,3 @@ public class AddStampMultipartRequest
     /// <example>Confidential</example>
     public PredefinedStampType? PredefinedType { get; set; }
 }
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF stamp operation (API layer only - converts to AddStampCommand)
-/// </summary>
-public record AddStampBase64Request
-{
-    /// <summary>
-    /// Base64-encoded PDF file
-    /// </summary>
-    /// <example>"JVBERi0xLjQK..."</example>
-    public required string Base64Pdf { get; init; }
-
-    /// <summary>
-    /// Type of stamp (Text, Image, or Predefined)
-    /// </summary>
-    /// <example>Text</example>
-    public required StampType StampType { get; init; }
-
-    /// <summary>
-    /// Target page numbers (1-indexed). Null or empty = all pages.
-    /// </summary>
-    /// <example>[1, 3, 5]</example>
-    public int[]? PageNumbers { get; init; }
-
-    /// <summary>
-    /// Stamp position X coordinate
-    /// </summary>
-    /// <example>100.0</example>
-    public required double X { get; init; }
-
-    /// <summary>
-    /// Stamp position Y coordinate
-    /// </summary>
-    /// <example>100.0</example>
-    public required double Y { get; init; }
-
-    /// <summary>
-    /// Stamp width (optional, auto-size for images if not specified)
-    /// </summary>
-    /// <example>200.0</example>
-    public double? Width { get; init; }
-
-    /// <summary>
-    /// Stamp height (optional, auto-size for images if not specified)
-    /// </summary>
-    /// <example>50.0</example>
-    public double? Height { get; init; }
-
-    /// <summary>
-    /// Coordinate origin (BottomLeft = PDF native, TopLeft = UI-friendly). Default: BottomLeft
-    /// </summary>
-    /// <example>BottomLeft</example>
-    public AnnotationOrigin Origin { get; init; } = AnnotationOrigin.BottomLeft;
-
-    /// <summary>
-    /// Text content (required for Text stamps)
-    /// </summary>
-    /// <example>"CONFIDENTIAL"</example>
-    public string? Text { get; init; }
-
-    /// <summary>
-    /// Font name (default: Arial)
-    /// </summary>
-    /// <example>"Arial"</example>
-    public string? FontName { get; init; }
-
-    /// <summary>
-    /// Font size in points (default: 12)
-    /// </summary>
-    /// <example>24.0</example>
-    public double? FontSize { get; init; }
-
-    /// <summary>
-    /// Hex color (6 digits, e.g., "FF0000" for red, default: "000000")
-    /// </summary>
-    /// <example>"FF0000"</example>
-    public string? Color { get; init; }
-
-    /// <summary>
-    /// Opacity (0.0 = transparent, 1.0 = opaque, default: 0.5)
-    /// </summary>
-    /// <example>0.5</example>
-    public double? Opacity { get; init; }
-
-    /// <summary>
-    /// Rotation angle in degrees (0-360, default: 0)
-    /// </summary>
-    /// <example>45.0</example>
-    public double? Rotation { get; init; }
-
-    /// <summary>
-    /// Stamp placement (Foreground = on top, Background = watermark effect, default: Foreground)
-    /// </summary>
-    /// <example>Foreground</example>
-    public StampPlacement Placement { get; init; } = StampPlacement.Foreground;
-
-    /// <summary>
-    /// Base64-encoded image (required for Image stamps, PNG/JPEG)
-    /// </summary>
-    /// <example>"iVBORw0KGgoAAAANSUhEUgAA..."</example>
-    public string? Base64Image { get; init; }
-
-    /// <summary>
-    /// Predefined stamp type (required for Predefined stamps)
-    /// </summary>
-    /// <example>Confidential</example>
-    public PredefinedStampType? PredefinedType { get; init; }
-}

DocumentService.API/Controllers/PdfValidationController.cs

@@ -1,7 +1,7 @@
 using DocumentService.Application.Common.DTOs;
 using DocumentService.Application.ValidatePdf.Queries;
 using DocumentService.Application.ValidatePdfA.Queries;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using DocumentService.Domain.Common.Exceptions;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;

DocumentService.API/Controllers/SwissQrCodeController.cs

@@ -1,4 +1,5 @@
 using DocumentService.Application.Common.DTOs;
+using DocumentService.Application.Common.DTOs.Requests;
 using DocumentService.Application.SwissQrCode.Queries;
 using DocumentService.Domain.Common.Exceptions;
 using MediatR;
@@ -100,14 +101,3 @@ public class SwissQrCodeController(IMediator Mediator) : ControllerBase
     }
 }
 
-/// <summary>
-/// Request DTO for Base64-encoded Swiss QR Code extraction
-/// </summary>
-public record ExtractSwissQrCodeBase64Request
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}

DocumentService.API/Controllers/ZugferdController.cs

@@ -1,7 +1,7 @@
 using DocumentService.Application.Common.DTOs;
 using DocumentService.Application.ExtractZugferd;
 using DocumentService.Application.HasZugferd.Queries;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using DocumentService.Domain.Common.Exceptions;
 using MediatR;
 using Microsoft.AspNetCore.Http;

DocumentService.API/DocumentService.API.csproj

@@ -9,10 +9,10 @@
     <Authors>Digital Data GmbH</Authors>
     <Company>Digital Data GmbH</Company>
     <Product>DocumentOperator.API</Product>
-    <Version>1.0.0</Version>
-    <FileVersion>1.0.0.0</FileVersion>
-    <AssemblyVersion>1.0.0.0</AssemblyVersion>
-    <InformationalVersion>1.0.0</InformationalVersion>
+    <Version>1.1.0</Version>
+    <FileVersion>1.1.0.0</FileVersion>
+    <AssemblyVersion>1.1.0.0</AssemblyVersion>
+    <InformationalVersion>1.1.0</InformationalVersion>
     <Copyright>Copyright © 2026 Digital Data GmbH. All rights reserved.</Copyright>
     <Description>PDF Document Operations REST API - Validation, Swiss QR Code extraction, attachments, merge, annotation, stamp operations powered by DevExpress Office File API</Description>
     <PackageTags>pdf document operator validation swiss-qr-code annotations stamp devexpress</PackageTags>
@@ -32,10 +32,10 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\DocumentOperator.Application\DocumentService.Application.csproj" />
-    <ProjectReference Include="..\DocumentOperator.Domain\DocumentService.Domain.csproj" />
-    <ProjectReference Include="..\DocumentOperator.Infrastructure\DocumentService.Infrastructure.csproj" />
+    <ProjectReference Include="..\DocumentService.Application\DocumentService.Application.csproj" />
     <ProjectReference Include="..\DocumentService.Client\DocumentService.Client.csproj" />
+    <ProjectReference Include="..\DocumentService.Domain\DocumentService.Domain.csproj" />
+    <ProjectReference Include="..\DocumentService.Infrastructure\DocumentService.Infrastructure.csproj" />
   </ItemGroup>
 
 </Project>

DocumentService.Application/Common/DTOs/PdfValidationResult.cs

@@ -9,10 +9,12 @@ namespace DocumentService.Application.Common.DTOs;
 /// <param name="PdfVersion">PDF-Version (z.B. "1.4")</param>
 /// <param name="HasAttachments">Hat das PDF Anhänge?</param>
 /// <param name="AttachmentCount">Anzahl der Anhänge</param>
+/// <param name="IsEncrypted">Ist das PDF passwortgeschützt/verschlüsselt?</param>
 public record PdfValidationResult(
     int PageCount,
     long FileSizeBytes,
     double FileSizeMB,
     string PdfVersion,
     bool HasAttachments,
-    int AttachmentCount);
+    int AttachmentCount,
+    bool IsEncrypted);

DocumentService.Application/Common/DTOs/Requests/PdfAttachmentRequests.cs

@@ -1,40 +1,20 @@
-namespace DocumentService.Client.Models.Requests;
+namespace DocumentService.Application.Common.DTOs.Requests;
 
 /// <summary>
 /// Request DTO for Base64-encoded PDF attachment check
 /// </summary>
-public record CheckPdfAttachmentsRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}
+public record CheckPdfAttachmentsRequest : PdfBase64RequestBase;
 
 /// <summary>
 /// Request DTO for Base64-encoded PDF attachment extraction
 /// </summary>
-public record ExtractPdfAttachmentsRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}
+public record ExtractPdfAttachmentsRequest : PdfBase64RequestBase;
 
 /// <summary>
 /// Request DTO for Base64-encoded PDF with attachments to add
 /// </summary>
-public record AddAttachmentsRequest
+public record AddAttachmentsRequest : PdfBase64RequestBase
 {
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-
     /// <summary>
     /// List of attachments to embed
     /// </summary>
@@ -42,7 +22,7 @@ public record AddAttachmentsRequest
 }
 
 /// <summary>
-/// DTO for attachment file in request
+/// DTO for a single attachment file in a request
 /// </summary>
 public record AttachmentRequestDto
 {

DocumentService.Application/Common/DTOs/Requests/PdfBase64RequestBase.cs

@@ -1,9 +1,10 @@
-namespace DocumentService.Client.Models.Requests;
+namespace DocumentService.Application.Common.DTOs.Requests;
 
 /// <summary>
-/// Request DTO for Base64-encoded Swiss QR Code extraction
+/// Base record for all single-PDF Base64 request types.
+/// Provides the common <see cref="Base64Pdf"/> property shared across endpoints.
 /// </summary>
-public record ExtractSwissQrCodeBase64Request
+public abstract record PdfBase64RequestBase
 {
     /// <summary>
     /// PDF document encoded as Base64 string

DocumentService.Application/Common/DTOs/Requests/PdfConversionRequests.cs

@@ -0,0 +1,18 @@
+namespace DocumentService.Application.Common.DTOs.Requests;
+
+/// <summary>
+/// Request DTO for converting a standard PDF to PDF/A format (Base64 JSON)
+/// </summary>
+public record ConvertToPdfARequest : PdfBase64RequestBase
+{
+    /// <summary>
+    /// Target PDF/A conformance level. Defaults to "PDF/A-3b".
+    /// </summary>
+    /// <example>PDF/A-3b</example>
+    public string? PdfALevel { get; init; }
+}
+
+/// <summary>
+/// Request DTO for converting a PDF/A document back to standard PDF (Base64 JSON)
+/// </summary>
+public record ConvertFromPdfARequest : PdfBase64RequestBase;

DocumentService.Application/Common/DTOs/Requests/PdfOperationRequests.cs

@@ -1,6 +1,6 @@
-using DocumentService.Client.Models.ValueObjects;
+using DocumentService.Domain.Models.ValueObjects;
 
-namespace DocumentService.Client.Models.Requests;
+namespace DocumentService.Application.Common.DTOs.Requests;
 
 /// <summary>
 /// Request DTO for Base64-encoded PDF merge operation
@@ -25,14 +25,8 @@ public record MergePdfsBase64Request
 /// <summary>
 /// Request DTO for Base64-encoded PDF annotation
 /// </summary>
-public record AddAnnotationBase64Request
+public record AddAnnotationBase64Request : PdfBase64RequestBase
 {
-    /// <summary>
-    /// Base64-encoded PDF file
-    /// </summary>
-    /// <example>"JVBERi0xLjQK..."</example>
-    public required string Base64Pdf { get; init; }
-
     /// <summary>
     /// Type of annotation to add
     /// </summary>
@@ -115,14 +109,8 @@ public record AddAnnotationBase64Request
 /// <summary>
 /// Request DTO for Base64-encoded PDF stamp operation
 /// </summary>
-public record AddStampBase64Request
+public record AddStampBase64Request : PdfBase64RequestBase
 {
-    /// <summary>
-    /// Base64-encoded PDF file
-    /// </summary>
-    /// <example>"JVBERi0xLjQK..."</example>
-    public required string Base64Pdf { get; init; }
-
     /// <summary>
     /// Type of stamp (Text, Image, or Predefined)
     /// </summary>

DocumentService.Application/Common/DTOs/Requests/PdfValidationRequests.cs

@@ -0,0 +1,11 @@
+namespace DocumentService.Application.Common.DTOs.Requests;
+
+/// <summary>
+/// Request DTO for Base64-encoded PDF validation
+/// </summary>
+public record ValidatePdfBase64Request : PdfBase64RequestBase;
+
+/// <summary>
+/// Request DTO for Base64-encoded PDF/A validation
+/// </summary>
+public record ValidatePdfABase64Request : PdfBase64RequestBase;

DocumentService.Application/Common/DTOs/Requests/SwissQrCodeRequests.cs

@@ -0,0 +1,6 @@
+namespace DocumentService.Application.Common.DTOs.Requests;
+
+/// <summary>
+/// Request DTO for Base64-encoded Swiss QR Code extraction
+/// </summary>
+public record ExtractSwissQrCodeBase64Request : PdfBase64RequestBase;

DocumentService.Application/Common/DTOs/Requests/ZugferdRequests.cs

@@ -0,0 +1,11 @@
+namespace DocumentService.Application.Common.DTOs.Requests;
+
+/// <summary>
+/// Request DTO for Base64-encoded PDF ZUGFeRD check
+/// </summary>
+public record HasZugferdRequest : PdfBase64RequestBase;
+
+/// <summary>
+/// Request DTO for Base64-encoded PDF ZUGFeRD extraction
+/// </summary>
+public record ExtractZugferdRequest : PdfBase64RequestBase;

DocumentService.Application/Common/DTOs/SwissQrCodeExtractionResult.cs

@@ -32,6 +32,10 @@ namespace DocumentService.Application.Common.DTOs;
 /// }
 /// </example>
 public record SwissQrCodeExtractionResult(
+#if NET
     SwissQrBillDto Bill,
-    IReadOnlyList<string> RawLines
-);
+#else
+    object? Bill,
+#endif
+    IEnumerable<string> RawLines
+);

DocumentService.Application/Common/Interfaces/IPdfProcessor.cs

@@ -15,7 +15,7 @@ public interface IPdfProcessor
     /// <exception cref="Domain.Common.Exceptions.BadRequestException">
     /// Thrown when stream is empty, invalid, or not positioned at the beginning
     /// </exception>
-    Task<PdfMetadata> ValidateAsync(Stream pdfStream);
+    Task<PdfValidationResult> ValidateAsync(Stream pdfStream);
 
     /// <summary>
     /// Validates a PDF/A document and checks conformance level.
@@ -28,7 +28,7 @@ public interface IPdfProcessor
     /// <exception cref="Domain.Common.Exceptions.BadRequestException">
     /// Thrown when stream is empty, invalid, or not positioned at the beginning
     /// </exception>
-    Task<PdfAMetadata> ValidatePdfAAsync(Stream pdfStream);
+    Task<PdfAValidationResult> ValidatePdfAAsync(Stream pdfStream);
 
     /// <summary>
     /// Checks for embedded files (attachments) in a PDF document and returns detailed metadata.

DocumentService.Application/Common/Mapping/MappingProfile.cs

@@ -13,12 +13,6 @@ public class MappingProfile : Profile
 {
     public MappingProfile()
     {
-        // PdfMetadata -> PdfValidationResult
-        CreateMap<PdfMetadata, PdfValidationResult>();
-
-        // PdfAMetadata -> PdfAValidationResult
-        CreateMap<PdfAMetadata, PdfAValidationResult>()
-            .ForMember(dest => dest.FileSize, opt => opt.MapFrom(src => src.FileSizeBytes));
 
         // Codecrete Bill -> SwissQrBillDto
         CreateMap<Bill, SwissQrBillDto>()

DocumentService.Application/DocumentService.Application.csproj

@@ -0,0 +1,65 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>net462;net480;net8.0</TargetFrameworks>
+    <ImplicitUsings>enable</ImplicitUsings>
+	<Nullable>enable</Nullable>
+	<LangVersion>latest</LangVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Remove="DependencyInjection\**" />
+    <Compile Remove="Features\**" />
+    <EmbeddedResource Remove="DependencyInjection\**" />
+    <EmbeddedResource Remove="Features\**" />
+    <None Remove="DependencyInjection\**" />
+    <None Remove="Features\**" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
+    <PackageReference Include="AutoMapper" Version="16.2.0" />
+    <PackageReference Include="Codecrete.SwissQRBill.Generator" Version="3.4.0" />
+    <PackageReference Include="FluentValidation" Version="12.1.1" />
+    <PackageReference Include="FluentValidation.DependencyInjectionExtensions" Version="12.1.1" />
+    <PackageReference Include="MediatR" Version="14.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="10.0.10" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net462'">
+    <PackageReference Include="AutoMapper" Version="16.2.0" />
+    <PackageReference Include="FluentValidation" Version="11.11.0" />
+    <PackageReference Include="MediatR" Version="14.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="8.0.2" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net480'">
+    <PackageReference Include="AutoMapper" Version="16.2.0" />
+    <PackageReference Include="FluentValidation" Version="11.11.0" />
+    <PackageReference Include="MediatR" Version="14.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="8.0.2" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' != 'net8.0'">
+    <PackageReference Include="PolySharp" Version="1.14.1">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' != 'net8.0'">
+    <Compile Remove="Common\Interfaces\ISwissQrCodeProcessor.cs" />
+    <Compile Remove="Common\DTOs\SwissQrBillDto.cs" />
+    <Compile Remove="Common\Mapping\MappingProfile.cs" />
+    <Compile Remove="SwissQrCode\**" />
+    <Compile Remove="HasZugferd\**" />
+    <Compile Remove="DependencyInjection.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DocumentService.Domain\DocumentService.Domain.csproj" />
+  </ItemGroup>
+
+</Project>

DocumentService.Application/ExtractZugferd/ExtractZugferdCommand.cs

@@ -18,6 +18,7 @@ public record ExtractZugferdCommand : IRequest<ZugferdExtractionResult>
     public required Stream PdfStream { get; init; }
 }
 
+#if NET
 /// <summary>
 /// Handler for ExtractZugferdCommand.
 /// Extracts ZUGFeRD XML from PDF and returns XML content
@@ -77,6 +78,7 @@ public class ExtractZugferdCommandHandler(
         };
     }
 }
+#endif
 
 /// <summary>
 /// Validator for ExtractZugferdCommand.

DocumentService.Application/ValidatePdf/Queries/ValidatePdfQuery.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 ValidatePdfQuery : IRequest<PdfValidationResult>
 
 /// <summary>
 /// Handler for ValidatePdfQuery
-/// Orchestrates PDF validation using IPdfProcessor and AutoMapper
 /// </summary>
-public class ValidatePdfQueryHandler(IPdfProcessor PdfProcessor, IMapper Mapper) 
+public class ValidatePdfQueryHandler(IPdfProcessor pdfProcessor) 
     : IRequestHandler<ValidatePdfQuery, PdfValidationResult>
 {
-    /// <summary>
-    /// Validates PDF and returns metadata
-    /// </summary>
     public async Task<PdfValidationResult> Handle(ValidatePdfQuery request, CancellationToken cancellationToken)
     {
-        // Call DevExpress service directly with stream (exceptions propagate naturally)
-        var metadata = await PdfProcessor.ValidateAsync(request.PdfStream);
-
-        // Map DTO to response DTO using AutoMapper
-        return Mapper.Map<PdfValidationResult>(metadata);
+        return await pdfProcessor.ValidateAsync(request.PdfStream);
     }
 }

DocumentService.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);
     }
 }

DocumentService.Client/Clients/PdfAttachmentClient.cs

@@ -1,5 +1,6 @@
+using DocumentService.Application.Common.DTOs;
 using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using Microsoft.Extensions.Logging;
 using System.IO.Compression;
 using System.Net.Http;

DocumentService.Client/Clients/PdfConversionClient.cs

@@ -1,5 +1,5 @@
 using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using Microsoft.Extensions.Logging;
 using System.Net.Http;
 

DocumentService.Client/Clients/PdfOperationsClient.cs

@@ -1,5 +1,5 @@
 using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using Microsoft.Extensions.Logging;
 using System.Net.Http;
 using System.Net.Http.Headers;

DocumentService.Client/Clients/PdfValidationClient.cs

@@ -1,5 +1,6 @@
+using DocumentService.Application.Common.DTOs;
 using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using Microsoft.Extensions.Logging;
 using System.Net.Http;
 

DocumentService.Client/Clients/SwissQrCodeClient.cs

@@ -1,5 +1,6 @@
+using DocumentService.Application.Common.DTOs;
 using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using Microsoft.Extensions.Logging;
 using System.Net.Http;
 

DocumentService.Client/Clients/ZugferdClient.cs

@@ -1,5 +1,7 @@
+using DocumentService.Application.Common.DTOs;
+using DocumentService.Application.ExtractZugferd;
 using DocumentService.Client.Interfaces;
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 using Microsoft.Extensions.Logging;
 using System.Net.Http;
 

DocumentService.Client/DocumentService.Client.csproj

@@ -42,5 +42,9 @@
 			<PackagePath>\</PackagePath>
 		</None>
 	</ItemGroup>
+	
+	<ItemGroup>
+	  <ProjectReference Include="..\DocumentService.Application\DocumentService.Application.csproj" />
+	</ItemGroup>
 
 </Project>

DocumentService.Client/Interfaces/IPdfAttachmentClient.cs

@@ -1,4 +1,5 @@
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs;
+using DocumentService.Application.Common.DTOs.Requests;
 
 namespace DocumentService.Client.Interfaces;
 
@@ -60,30 +61,4 @@ public interface IPdfAttachmentClient
     /// <returns>Modified PDF as stream</returns>
     [Obsolete("API endpoint not implemented yet")]
     Task<Stream> AddAttachmentsAsync(byte[] pdfBytes, List<AttachmentRequestDto> attachments, CancellationToken cancellationToken = default);
-}
-
-/// <summary>
-/// DTO for attachment check result
-/// </summary>
-public record AttachmentCheckResult
-{
-    /// <summary>Whether the document contains any embedded file attachments.</summary>
-    public bool HasAttachments { get; init; }
-    /// <summary>Number of embedded file attachments found.</summary>
-    public int AttachmentCount { get; init; }
-    /// <summary>Metadata for each attachment found in the document.</summary>
-    public List<AttachmentMetadata> Attachments { get; init; } = new();
-}
-
-/// <summary>
-/// DTO for attachment metadata
-/// </summary>
-public record AttachmentMetadata
-{
-    /// <summary>Name of the embedded file.</summary>
-    public string FileName { get; init; } = string.Empty;
-    /// <summary>MIME type of the embedded file (e.g. "application/xml"), or <c>null</c> if unknown.</summary>
-    public string? MimeType { get; init; }
-    /// <summary>Size of the embedded file in bytes.</summary>
-    public long Size { get; init; }
-}
+}

DocumentService.Client/Interfaces/IPdfOperationsClient.cs

@@ -1,4 +1,4 @@
-using DocumentService.Client.Models.Requests;
+using DocumentService.Application.Common.DTOs.Requests;
 
 namespace DocumentService.Client.Interfaces;
 

DocumentService.Client/Interfaces/IPdfValidationClient.cs

@@ -1,3 +1,5 @@
+using DocumentService.Application.Common.DTOs;
+
 namespace DocumentService.Client.Interfaces;
 
 /// <summary>
@@ -36,40 +38,4 @@ public interface IPdfValidationClient
     /// <param name="cancellationToken">Cancellation token</param>
     /// <returns>PDF/A validation result with conformance level and errors</returns>
     Task<PdfAValidationResult> ValidatePdfAAsync(byte[] pdfBytes, CancellationToken cancellationToken = default);
-}
-
-/// <summary>
-/// DTO for PDF validation result
-/// </summary>
-public record PdfValidationResult
-{
-    /// <summary>Total number of pages in the document.</summary>
-    public int PageCount { get; init; }
-    /// <summary>File size in bytes.</summary>
-    public long FileSizeBytes { get; init; }
-    /// <summary>PDF specification version (e.g. "1.7").</summary>
-    public string PdfVersion { get; init; } = string.Empty;
-    /// <summary>Whether the document is password-protected.</summary>
-    public bool IsEncrypted { get; init; }
-    /// <summary>Whether the document contains embedded file attachments.</summary>
-    public bool HasAttachments { get; init; }
-    /// <summary>Number of embedded file attachments.</summary>
-    public int AttachmentCount { get; init; }
-}
-
-/// <summary>
-/// DTO for PDF/A validation result
-/// </summary>
-public record PdfAValidationResult
-{
-    /// <summary>Whether the document is fully PDF/A conformant.</summary>
-    public bool IsValid { get; init; }
-    /// <summary>Detected PDF/A conformance level (e.g. "PDF/A-3b"), or <c>null</c> if not a PDF/A document.</summary>
-    public string? PdfAVersion { get; init; }
-    /// <summary>Total number of pages in the document.</summary>
-    public int PageCount { get; init; }
-    /// <summary>List of conformance errors found during validation.</summary>
-    public List<string> Errors { get; init; } = new();
-    /// <summary>List of conformance warnings found during validation.</summary>
-    public List<string> Warnings { get; init; } = new();
-}
+}

DocumentService.Client/Interfaces/ISwissQrCodeClient.cs

@@ -1,3 +1,5 @@
+using DocumentService.Application.Common.DTOs;
+
 namespace DocumentService.Client.Interfaces;
 
 /// <summary>
@@ -24,13 +26,3 @@ public interface ISwissQrCodeClient
     Task<SwissQrCodeExtractionResult> ExtractSwissQrCodeAsync(byte[] pdfBytes, bool raw = false, CancellationToken cancellationToken = default);
 }
 
-/// <summary>
-/// DTO for Swiss QR Code extraction result
-/// </summary>
-public record SwissQrCodeExtractionResult
-{
-    /// <summary>Parsed Swiss QR bill object. <c>null</c> when <c>raw=true</c> was requested.</summary>
-    public object? Bill { get; init; }
-    /// <summary>Raw QR code text lines. Populated when <c>raw=true</c> was requested.</summary>
-    public List<string> RawLines { get; init; } = new();
-}

DocumentService.Client/Interfaces/IZugferdClient.cs

@@ -1,3 +1,6 @@
+using DocumentService.Application.Common.DTOs;
+using DocumentService.Application.ExtractZugferd;
+
 namespace DocumentService.Client.Interfaces;
 
 /// <summary>
@@ -53,27 +56,3 @@ public interface IZugferdClient
     /// <returns>Structured ZUGFeRD extraction result</returns>
     Task<ZugferdExtractionResult> ExtractZugferdAsResultAsync(byte[] pdfBytes, CancellationToken cancellationToken = default);
 }
-
-/// <summary>DTO for ZUGFeRD detection result</summary>
-public record ZugferdCheckResult
-{
-    /// <summary>Whether the document contains a ZUGFeRD XML attachment.</summary>
-    public bool HasZugferd { get; init; }
-    /// <summary>Detected ZUGFeRD version (e.g. "2.1"), or <c>null</c> if not present.</summary>
-    public string? Version { get; init; }
-    /// <summary>ZUGFeRD profile name (e.g. "EN 16931"), or <c>null</c> if not present.</summary>
-    public string? Profile { get; init; }
-}
-
-/// <summary>DTO for ZUGFeRD extraction result</summary>
-public record ZugferdExtractionResult
-{
-    /// <summary>File name of the extracted XML attachment (e.g. "factur-x.xml").</summary>
-    public string FileName { get; init; } = string.Empty;
-    /// <summary>Full XML content of the ZUGFeRD attachment.</summary>
-    public string XmlContent { get; init; } = string.Empty;
-    /// <summary>ZUGFeRD version (e.g. "2.1"), or <c>null</c> if not detected.</summary>
-    public string? Version { get; init; }
-    /// <summary>ZUGFeRD profile name (e.g. "EN 16931"), or <c>null</c> if not detected.</summary>
-    public string? Profile { get; init; }
-}

DocumentService.Client/Models/Requests/PdfConversionRequests.cs

@@ -1,31 +0,0 @@
-namespace DocumentService.Client.Models.Requests;
-
-/// <summary>
-/// Request DTO for converting a standard PDF to PDF/A format (Base64 JSON)
-/// </summary>
-public record ConvertToPdfARequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-
-    /// <summary>
-    /// Target PDF/A conformance level. Defaults to "PDF/A-3b".
-    /// </summary>
-    /// <example>PDF/A-3b</example>
-    public string? PdfALevel { get; init; }
-}
-
-/// <summary>
-/// Request DTO for converting a PDF/A document back to standard PDF (Base64 JSON)
-/// </summary>
-public record ConvertFromPdfARequest
-{
-    /// <summary>
-    /// PDF/A document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}

DocumentService.Client/Models/Requests/PdfValidationRequests.cs

@@ -1,27 +0,0 @@
-using DocumentService.Client.Models.ValueObjects;
-
-namespace DocumentService.Client.Models.Requests;
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF validation
-/// </summary>
-public record ValidatePdfBase64Request
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF/A validation
-/// </summary>
-public record ValidatePdfABase64Request
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}

DocumentService.Client/Models/Requests/ZugferdRequests.cs

@@ -1,25 +0,0 @@
-namespace DocumentService.Client.Models.Requests;
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF ZUGFeRD check
-/// </summary>
-public record HasZugferdRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}
-
-/// <summary>
-/// Request DTO for Base64-encoded PDF ZUGFeRD extraction
-/// </summary>
-public record ExtractZugferdRequest
-{
-    /// <summary>
-    /// PDF document encoded as Base64 string
-    /// </summary>
-    /// <example>JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL0NhdGFsb2c...</example>
-    public required string Base64Pdf { get; init; }
-}

DocumentService.Client/Models/ValueObjects/AnnotationOrigin.cs

@@ -1,17 +0,0 @@
-namespace DocumentService.Client.Models.ValueObjects;
-
-/// <summary>
-/// Coordinate origin point for PDF annotations.
-/// </summary>
-public enum AnnotationOrigin
-{
-    /// <summary>
-    /// Bottom-left corner (PDF native coordinate system, default)
-    /// </summary>
-    BottomLeft,
-    
-    /// <summary>
-    /// Top-left corner (common in UI frameworks)
-    /// </summary>
-    TopLeft
-}

DocumentService.Client/Models/ValueObjects/AnnotationType.cs

@@ -1,32 +0,0 @@
-namespace DocumentService.Client.Models.ValueObjects;
-
-/// <summary>
-/// Supported PDF annotation types
-/// </summary>
-public enum AnnotationType
-{
-    /// <summary>
-    /// Text markup annotation (highlight, underline, strikeout)
-    /// </summary>
-    TextMarkup,
-    
-    /// <summary>
-    /// Free text annotation (text box with visible text)
-    /// </summary>
-    FreeText,
-    
-    /// <summary>
-    /// Sticky note annotation (popup comment icon)
-    /// </summary>
-    StickyNote,
-    
-    /// <summary>
-    /// Circle shape annotation
-    /// </summary>
-    Circle,
-    
-    /// <summary>
-    /// Square shape annotation
-    /// </summary>
-    Square
-}

DocumentService.Client/Models/ValueObjects/PredefinedStampType.cs

@@ -1,32 +0,0 @@
-namespace DocumentService.Client.Models.ValueObjects;
-
-/// <summary>
-/// Predefined stamp types with standard text and styling.
-/// </summary>
-public enum PredefinedStampType
-{
-    /// <summary>
-    /// CONFIDENTIAL stamp (red, bold).
-    /// </summary>
-    Confidential,
-
-    /// <summary>
-    /// APPROVED stamp (green, bold).
-    /// </summary>
-    Approved,
-
-    /// <summary>
-    /// DRAFT stamp (gray, italic).
-    /// </summary>
-    Draft,
-
-    /// <summary>
-    /// VOID stamp (red, strikethrough effect).
-    /// </summary>
-    Void,
-
-    /// <summary>
-    /// FOR REVIEW stamp (orange, bold).
-    /// </summary>
-    ForReview
-}

DocumentService.Client/Models/ValueObjects/StampPlacement.cs

@@ -1,17 +0,0 @@
-namespace DocumentService.Client.Models.ValueObjects;
-
-/// <summary>
-/// Specifies whether the stamp should appear in the foreground or background.
-/// </summary>
-public enum StampPlacement
-{
-    /// <summary>
-    /// Stamp appears on top of existing page content.
-    /// </summary>
-    Foreground,
-
-    /// <summary>
-    /// Stamp appears behind existing page content (watermark effect).
-    /// </summary>
-    Background
-}

DocumentService.Client/Models/ValueObjects/StampType.cs

@@ -1,22 +0,0 @@
-namespace DocumentService.Client.Models.ValueObjects;
-
-/// <summary>
-/// Specifies the type of stamp to add to a PDF document.
-/// </summary>
-public enum StampType
-{
-    /// <summary>
-    /// Text-based stamp with custom text, font, and color.
-    /// </summary>
-    Text,
-
-    /// <summary>
-    /// Image-based stamp (PNG/JPEG overlay).
-    /// </summary>
-    Image,
-
-    /// <summary>
-    /// Predefined stamp with standard text (e.g., CONFIDENTIAL, APPROVED).
-    /// </summary>
-    Predefined
-}

DocumentService.Client/Models/ValueObjects/TextMarkupStyle.cs

@@ -1,22 +0,0 @@
-namespace DocumentService.Client.Models.ValueObjects;
-
-/// <summary>
-/// Text markup annotation style (highlight, underline, strikeout)
-/// </summary>
-public enum TextMarkupStyle
-{
-    /// <summary>
-    /// Highlight text with background color
-    /// </summary>
-    Highlight,
-    
-    /// <summary>
-    /// Underline text
-    /// </summary>
-    Underline,
-    
-    /// <summary>
-    /// Strikeout text (strikethrough)
-    /// </summary>
-    Strikeout
-}

DocumentService.Client/STREAM_API_DESIGN.md

@@ -1,230 +0,0 @@
-# DocumentService.Client - Stream-Based API
-
-## ?? Design Decision: Why Stream Instead of byte[]?
-
-### ? **Advantages of Stream-Based Returns**
-
-| **Aspect** | **Stream** | **byte[]** |
-|---|---|---|
-| **Memory Efficiency** | ????? | ?? |
-| **Flexibility** | ????? | ??? |
-| **Large Files** | ? Excellent | ? Poor (OutOfMemoryException risk) |
-| **Direct File Save** | ? `CopyToAsync(fileStream)` | ? Must buffer entire file |
-| **Streaming to Response** | ? Direct pipe | ? Must load to memory first |
-| **Base64 Conversion** | ? Extension method | ? `Convert.ToBase64String()` |
-| **Network Transfer** | ? Progressive | ? Buffered |
-
----
-
-## ?? Extension Methods
-
-### `StreamExtensions` - Converting Streams
-
-```csharp
-using DocumentService.Client.Extensions;
-
-// Convert Stream to Base64
-using var pdfStream = await client.Operations.MergeAsync(streams);
-string base64 = await pdfStream.ToBase64StringAsync();
-
-// Convert Stream to byte[]
-using var pdfStream = await client.Operations.MergeAsync(streams);
-byte[] bytes = await pdfStream.ToBytesAsync();
-
-// Reset stream position (if seekable)
-pdfStream.Reset(); // Position = 0
-```
-
----
-
-## ?? Usage Patterns
-
-### Pattern 1: Direct File Save (Memory Efficient ?)
-
-```csharp
-// ? Best for large files - no intermediate buffering
-using var pdfStream = await client.Operations.MergeAsync(streams);
-using var fileStream = File.Create("output.pdf");
-await pdfStream.CopyToAsync(fileStream);
-```
-
-### Pattern 2: HTTP Response Streaming (Memory Efficient ?)
-
-```csharp
-// ASP.NET Core example
-[HttpGet("merge")]
-public async Task<IActionResult> MergePdfs()
-{
-    using var mergedStream = await _client.Operations.MergeAsync(streams);
-    
-    // Stream directly to HTTP response - no buffering
-    return File(mergedStream, "application/pdf", "merged.pdf");
-}
-```
-
-### Pattern 3: Base64 Conversion (When Needed)
-
-```csharp
-// ?? Only if Base64 is required (e.g., JSON APIs, email attachments)
-using var pdfStream = await client.Operations.MergeAsync(streams);
-string base64Pdf = await pdfStream.ToBase64StringAsync();
-
-// Send to external API
-await externalApi.SendDocumentAsync(new { pdf = base64Pdf });
-```
-
-### Pattern 4: Byte Array (Legacy Compatibility)
-
-```csharp
-// ?? For legacy code that requires byte[]
-using var pdfStream = await client.Operations.MergeAsync(streams);
-byte[] pdfBytes = await pdfStream.ToBytesAsync();
-
-// Use with legacy method
-legacyService.ProcessPdf(pdfBytes);
-```
-
----
-
-## ?? Performance Comparison
-
-### Scenario: Merging 10 PDFs (100 MB total)
-
-| **Approach** | **Memory Usage** | **Speed** | **Scalability** |
-|---|---|---|---|
-| **Stream ? File** | ~10 MB | ????? | Excellent |
-| **Stream ? HTTP** | ~10 MB | ????? | Excellent |
-| **Stream ? byte[]** | ~110 MB | ??? | Limited |
-| **byte[] ? File** | ~210 MB | ?? | Poor |
-
-**Conclusion:** Stream-based API reduces memory footprint by **10-20x** for large files.
-
----
-
-## ?? API Reference
-
-### All Stream-Returning Methods
-
-| **Client** | **Method** | **Return Type** |
-|---|---|---|
-| **IPdfAttachmentClient** | `ExtractAttachmentsAsync()` | `Task<Stream>` |
-| **IPdfAttachmentClient** | `AddAttachmentsAsync()` | `Task<Stream>` |
-| **IPdfOperationsClient** | `MergeAsync()` | `Task<Stream>` |
-| **IPdfOperationsClient** | `AnnotateAsync()` | `Task<Stream>` |
-| **IPdfOperationsClient** | `StampAsync()` | `Task<Stream>` |
-
-**Query Methods** (Metadata only):
-- `IPdfValidationClient.ValidatePdfAsync()` ? `Task<PdfValidationResult>`
-- `IPdfAttachmentClient.CheckAttachmentsAsync()` ? `Task<AttachmentCheckResult>`
-- `ISwissQrCodeClient.ExtractSwissQrCodeAsync()` ? `Task<SwissQrCodeExtractionResult>`
-
----
-
-## ?? Stream Disposal Best Practices
-
-### ? Correct Usage
-
-```csharp
-// Pattern 1: using declaration (C# 8.0+)
-using var pdfStream = await client.Operations.MergeAsync(streams);
-// Auto-disposed at end of scope
-
-// Pattern 2: using statement
-using (var pdfStream = await client.Operations.MergeAsync(streams))
-{
-    // Use stream here
-} // Auto-disposed
-
-// Pattern 3: Manual disposal (not recommended)
-var pdfStream = await client.Operations.MergeAsync(streams);
-try
-{
-    // Use stream
-}
-finally
-{
-    pdfStream.Dispose();
-}
-```
-
-### ? Incorrect Usage (Memory Leak)
-
-```csharp
-// ? NO using - stream never disposed!
-var pdfStream = await client.Operations.MergeAsync(streams);
-await pdfStream.CopyToAsync(fileStream);
-// Memory leak!
-```
-
----
-
-## ?? .NET Framework Compatibility
-
-### Conditional Compilation for CopyToAsync
-
-```csharp
-// StreamExtensions.cs handles this internally
-#if NET8_0
-await stream.CopyToAsync(memoryStream, cancellationToken);
-#else
-await stream.CopyToAsync(memoryStream); // .NET Framework doesn't support CancellationToken
-#endif
-```
-
-### Supported Versions
-- ? .NET 8.0 - Full support with CancellationToken
-- ? .NET Framework 4.8 - Full support (no CancellationToken in CopyToAsync)
-- ? .NET Framework 4.6.2 - Full support (no CancellationToken in CopyToAsync)
-
----
-
-## ?? Migration from byte[] to Stream
-
-### Before (byte[]-based)
-
-```csharp
-byte[] mergedPdf = await client.Operations.MergeAsync(streams);
-await File.WriteAllBytesAsync("output.pdf", mergedPdf);
-```
-
-### After (Stream-based)
-
-```csharp
-using var mergedStream = await client.Operations.MergeAsync(streams);
-using var fileStream = File.Create("output.pdf");
-await mergedStream.CopyToAsync(fileStream);
-```
-
-### If you NEED byte[] (Legacy Code)
-
-```csharp
-using DocumentService.Client.Extensions;
-
-using var mergedStream = await client.Operations.MergeAsync(streams);
-byte[] mergedPdf = await mergedStream.ToBytesAsync(); // Extension method
-```
-
----
-
-## ?? Summary
-
-? **Stream-based API** for:
-- Memory efficiency
-- Large file support
-- Direct file/HTTP streaming
-- Flexibility (convert to byte[]/Base64 when needed)
-
-? **Extension methods** for:
-- `Stream.ToBase64StringAsync()`
-- `Stream.ToBytesAsync()`
-- `Stream.Reset()`
-
-? **Multi-target support**:
-- .NET 8.0
-- .NET Framework 4.8
-- .NET Framework 4.6.2
-
-? **Performance**:
-- 10-20x memory reduction for large files
-- Progressive streaming (no buffering)
-- Scalable for enterprise workloads

DocumentService.Domain/DocumentService.Domain.csproj

@@ -1,9 +1,10 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFrameworks>net462;net480;net8.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>enable</Nullable>
+	<Nullable>enable</Nullable>
+	<LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>