feat: Implement mfr truncation fix and enhance invoice handling

- Added a new SQL script to address the "String or binary data would be truncated" error in mfr sync by widening the Note fields in service objects and companies to NVARCHAR(MAX).
- Updated the table types and associated stored procedures to accommodate the changes, ensuring compatibility with existing data.
- Queued a re-sync for previously rejected rows due to truncation issues.
- Created application logins for fuchs_fds and fuchs_web with placeholder passwords for initial setup.
- Introduced functions for invoice backdating and invoice date retrieval to streamline invoice processing.
- Developed a password generation function with customizable parameters for length and character types.
- Added a random number generation function to support password creation.

Fuchs/Services/AzureBlobStorageService.cs

@@ -135,6 +135,12 @@ public class AzureBlobStorageService : IBlobStorageService
             Response<bool> response = await blobClient.ExistsAsync(cancellationToken);
             return response.Value;
         }
+        catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
+        {
+            // Caller cancelled (e.g. app shutdown during the startup backfill) — not a storage failure;
+            // reporting "not archived" here made the backfill go on to a doomed upload logged as an error.
+            throw;
+        }
         catch (Exception ex)
         {
             _logger.LogWarning(ex, "Blob existence check failed for {Container}/{Blob} — treating as not archived.",
@@ -270,6 +276,11 @@ public class AzureBlobStorageService : IBlobStorageService
                 category, documentId, containerName, blobName);
             return blobClient.Uri;
         }
+        catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
+        {
+            _logger.LogDebug("Blob upload cancelled for {Category} {Id} (caller cancelled).", category, documentId);
+            throw;
+        }
         catch (Exception ex)
         {
             FuchsTelemetry.BlobUploadsFailed.Add(1, new KeyValuePair<string, object?>("category", category));

Fuchs/Services/ERechnungMapper.cs

@@ -259,13 +259,7 @@ public static class ERechnungMapper
     }
 
     // ── helpers ────────────────────────────────────────────────────────────────
-    private static DateOnly IssueDate(GenericObjectDictionary? reg)
-    {
-        foreach (var key in new[] { "DateFinalized", "DateCreated" })
-            if (reg?.getString(key) is { Length: > 0 } s && DateTime.TryParse(s, CultureInfo.InvariantCulture, DateTimeStyles.None, out var dt))
-                return DateOnly.FromDateTime(dt);
-        return DateOnly.FromDateTime(DateTime.Today);
-    }
+    private static DateOnly IssueDate(GenericObjectDictionary? reg) => InvoiceDates.IssueDate(reg);
 
     /// <summary>Normalises a raw country value (ISO alpha-2, or a German/English name) to a country code.</summary>
     internal static CountryCode NormalizeCountry(string? raw)

Fuchs/Services/IBlobStorageService.cs

@@ -12,7 +12,8 @@ public interface IBlobStorageService
     /// supplied (typically <c>FdsInvoiceData.InvoiceRegistration</c>), blob metadata is projected from
     /// it using <see cref="AzureBlobStorageSettings.MetadataFields"/> — see <see cref="DocumentMetadataBuilder"/>.
     /// Returns the blob URI, or <c>null</c> when storage is disabled/unconfigured
-    /// or the upload failed — failures never break the primary DB-storage flow.
+    /// or the upload failed — failures never break the primary DB-storage flow. Only a cancelled
+    /// <paramref name="cancellationToken"/> surfaces, as <see cref="OperationCanceledException"/>.
     /// </summary>
     Task<Uri?> UploadInvoicePdfAsync(string invoiceId, string fileName, byte[] content,
         IReadOnlyDictionary<string, object?>? sourceRow = null, CancellationToken cancellationToken = default);
@@ -50,7 +51,8 @@ public interface IBlobStorageService
     /// <summary>
     /// Returns <c>true</c> if a blob already exists for the given container/document/filename
     /// combination. Used by the startup backfill to skip documents that were already archived.
-    /// Returns <c>false</c> (never throws) when storage is disabled/unconfigured or the check fails.
+    /// Returns <c>false</c> when storage is disabled/unconfigured or the check fails; throws only
+    /// <see cref="OperationCanceledException"/> when <paramref name="cancellationToken"/> is cancelled.
     /// </summary>
     Task<bool> ExistsAsync(string containerName, string documentId, string fileName,
         CancellationToken cancellationToken = default);

Fuchs/Services/InvoiceDraftEditService.cs

@@ -616,7 +616,8 @@ public sealed class InvoiceDraftEditService : IInvoiceDraftService
             ["SendToAddressJson"]  = InvoiceRecipientAddress.FromCustomValues(Str(session.New["CustomValues"]))?
                                         .ToJson().ToString(Newtonsoft.Json.Formatting.None) ?? "",
             ["InvoiceOptions"]     = BuildInvoiceOptions(session),
-            ["DateCreated"]        = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)
+            // UTC like the stored column — InvoiceDates.IssueDate converts it to the German day
+            ["DateCreated"]        = DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)
         };
 
         int idx = 0;

Fuchs/Services/InvoiceService.cs

@@ -205,6 +205,17 @@ public class InvoiceService : IInvoiceService
     /// The whole set is cleared and rewritten on every call — simpler and safer than diffing —
     /// mirroring the legacy <c>fds__invoice_data.RegisterInvoice_V1</c> (VB) behaviour.
     /// </summary>
+    /// <summary>
+    /// Normalises an item's posted <c>ref</c> (the invoice a CanceledInvoice / IntInvoiceAllocation line
+    /// points at) for <c>fds__invoice_items.reference_InvId</c> (varchar(20)); null when absent or not an id.
+    /// </summary>
+    internal static string? ItemReferenceInvId(string? raw)
+    {
+        string s = (raw ?? "").Trim();
+        if (s.Length == 0 || s.Length > 20 || s.Equals("null", StringComparison.OrdinalIgnoreCase)) return null;
+        return s.All(char.IsAsciiLetterOrDigit) ? s : null;
+    }
+
     private async Task PersistInvoiceLineItemsAsync(FdsInvoiceData invoice, string userAccountId, DatabaseSecurity dbSec)
     {
         string invoiceId = invoice.Id;
@@ -269,6 +280,7 @@ public class InvoiceService : IInvoiceService
                 float vs = 0;
                 if (TryCastSingle(itmDic.getItem("vs"), ref vs)) row["value_service"] = (decimal)vs;
                 row["det"]       = itmDic.no("det", false) is true;
+                if (ItemReferenceInvId(itmDic.nz("ref")) is { } refInvId) row["reference_InvId"] = refInvId;
                 row["SortOrder"] = (byte)Math.Clamp(itemSort, 0, 255);
                 itemsTable.Rows.Add(row);
             }
@@ -302,7 +314,9 @@ public class InvoiceService : IInvoiceService
                 : Array.Empty<string>(),
             AdminUser      = reg?.getString("UserNameFinalized") ?? "",
             AdminUserEmail = reg?.getString("UserEmailFinalized") ?? "",
-            AdminDatumValue = reg?.getString("DateCreated") is { Length: > 0 } dc ? DateTime.Parse(dc) : DateTime.Now
+            // Rechnungsdatum = DateFinalized (incl. backdating), draft: DateCreated — same source as the
+            // e-invoice issue date (ERechnungMapper), see InvoiceDates / ADR 0032.
+            AdminDatumValue = InvoiceDates.IssueDate(reg).ToDateTime(TimeOnly.MinValue)
         };
         var inlineImages = await ResolveInlineImagesAsync(invoice);
         var doc = await _pdf.WriteLetterAsync(tb, draft);

Fuchs/Services/ReminderDraftEditService.cs

@@ -271,7 +271,8 @@ public sealed class ReminderDraftEditService : IReminderDraftService
             ["invoices"]      = invoices,
             ["CustomValues"]  = Str(session.New["CustomValues"]),
             ["IsFinal"]       = false,
-            ["DateCreated"]   = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)
+            // UTC like the stored column — InvoiceDates.IssueDate converts it to the German day
+            ["DateCreated"]   = DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)
         };
         return new GenericObjectDictionary(d);
     }

Fuchs/Services/ReminderService.cs

@@ -111,7 +111,8 @@ public class ReminderService : IReminderService
             Address         = reminder.InvoiceAddress,
             AdminUser       = reminder.UserNameFinalized,
             AdminUserEmail  = reminder.UserEmailFinalized,
-            AdminDatumValue = reminder.DateCreated ?? DateTime.Now
+            // Reminder date = DateFinalized, draft: DateCreated — same rule as the invoice date (ADR 0035)
+            AdminDatumValue = InvoiceDates.IssueDate(reminder.ReminderRegistration).ToDateTime(TimeOnly.MinValue)
         };
         if (!string.IsNullOrEmpty(reminder.RawCustomValues))
         {