Add support for generating result PDFs

Introduced the `ResultFilePath` property in the `ZugferdInvoice` model to store the path of generated result PDFs. Added a new service, `PdfResultPackageService`, to create result PDFs by converting the original PDF to PDF/A-3b format and attaching a report file. Updated `Upload.cshtml` and `Upload.cshtml.cs` to handle and display the `ResultFilePath`.

Created a migration to add the `ResultFilePath` column to the database. Updated `Program.cs` to register the new service and added configuration sections in `appsettings.json` for input and output directories. Enhanced error handling and logging for better traceability.

DXApp.TemplateKitProject/Pages/Invoices/Upload.cshtml.cs

@@ -1,4 +1,5 @@
-using DXApp.TemplateKitProject.Models;
+using DXApp.TemplateKitProject.Data;
+using DXApp.TemplateKitProject.Models;
 using DXApp.TemplateKitProject.Services;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.RazorPages;
@@ -8,6 +9,8 @@ namespace DXApp.TemplateKitProject.Pages.Invoices;
 public class UploadModel(
     PdfAttachmentExtractorService extractor,
     ZugferdImportService zugferdImportService,
+    PdfResultPackageService resultPackageService,
+    AppDbContext db,
     ILogger<UploadModel> logger) : PageModel
 {
     [BindProperty]
@@ -17,6 +20,7 @@ public class UploadModel(
     public bool ExtractionDone { get; private set; }
     public string? ErrorMessage { get; private set; }
     public ZugferdInvoice? ImportedInvoice { get; private set; }
+    public string? ResultFilePath { get; private set; }
 
     public void OnGet()
     { }
@@ -42,8 +46,9 @@ public class UploadModel(
             // Stream in MemoryStream puffern → kann zweimal gelesen werden
             using var memStream = new MemoryStream();
             await PdfFile.CopyToAsync(memStream);
+            var originalBytes = memStream.ToArray();  // ← neu: als byte[] merken
 
-            // 1. Anhänge extrahieren und auf Disk speichern
+            // 1. Anhänge extrahieren
             memStream.Position = 0;
             Result = extractor.ExtractAttachments(memStream, PdfFile.FileName);
 
@@ -52,6 +57,20 @@ public class UploadModel(
             {
                 memStream.Position = 0;
                 ImportedInvoice = await zugferdImportService.ImportAsync(memStream, "Upload");
+
+                // 3. Result-Package erstellen (nur wenn Import erfolgreich)
+                if (ImportedInvoice is not null)
+                {
+                    ResultFilePath = await resultPackageService.CreateResultPackageAsync(
+                        originalBytes, PdfFile.FileName, ImportedInvoice);
+
+                    // ResultFilePath in DB aktualisieren
+                    if (ResultFilePath is not null)
+                    {
+                        ImportedInvoice.ResultFilePath = ResultFilePath;
+                        await db.SaveChangesAsync();
+                    }
+                }
             }
         }
         catch (Exception ex)