Enhance banking transaction data structure and validation

- Increased the length of the NameOfPayer field from NVARCHAR(60) to NVARCHAR(140) in the banking transactions function, table, temporary table, and user-defined type to accommodate longer names.
- Expanded the SepaRemittanceInformation field from VARCHAR(150) to VARCHAR(200) in the banking transactions function for more detailed remittance information.
- Modified the stored procedure fds__setBankingtransaction_done to return additional transaction data (ValueDate and Amount) along with the success flag for improved notification messaging.
- Added validation in MFRClientConfig constructor to ensure the provided URL is not null or empty, enhancing error handling for configuration settings.

Fuchs/Services/BankingService.cs

@@ -36,6 +36,7 @@ public class BankingService : IBankingService
         using var act = FuchsTelemetry.StartActivity("banking.parse");
         var sw = Stopwatch.StartNew();
         var tbl = schemaDatatable?.Clone() ?? BuildDefaultSchema();
+        ApplyKnownColumnWidths(tbl);
         var diag = new ParseDiagnostics();
 
         // Buffer once so we can sniff the format and (re)parse from the bytes.
@@ -280,6 +281,53 @@ public class BankingService : IBankingService
         }
     }
 
+    /// <summary>
+    /// The schema DataTable fetched from <c>[dbo].[fds__tt__bankingtransactions]</c> via
+    /// <c>SELECT TOP(0) * FROM @tmp</c> comes back with <see cref="DataColumn.MaxLength"/> = -1
+    /// for every string column — ADO.NET does not carry character-length facets through a
+    /// table-variable-typed SELECT. Without a real MaxLength, <see cref="SetCell"/>'s truncation
+    /// guard never engages, so an over-long real-world CAMT field (routine for rich SEPA
+    /// remittance/reference data) sails through parsing and the temp-table bulk copy — which
+    /// builds its columns from this same DataTable and creates them as NVARCHAR(MAX) — only to
+    /// throw "String or binary data would be truncated" once the merge stored procedure inserts
+    /// into the real, correctly-width-constrained target table. These widths mirror
+    /// [dbo].[fds__tt__bankingtransactions] / [dbo].[fds__bankingtransactions] (kept identical by
+    /// design) so truncation happens safely here instead of failing the whole import downstream.
+    /// </summary>
+    private static readonly Dictionary<string, int> KnownColumnMaxLengths = new()
+    {
+        ["AccountIdentification"]             = 50,
+        ["FundsCode"]                         = 1,
+        ["AccountNumberOfPayer"]              = 30,
+        ["BankCodeOfPayer"]                   = 11,
+        ["CompensationAmount"]                = 50,
+        ["CreditorReference"]                 = 30,
+        ["CreditorsReferenceParty"]           = 50,
+        ["CustomerReference"]                 = 50,
+        ["EndToEndReference"]                 = 50,
+        ["JournalNumber"]                     = 10,
+        ["MandateReference"]                  = 50,
+        ["NameOfPayer"]                        = 140, // ISO 20022 Max140Text — some banks put the full postal address in <Nm>, not just a name
+        ["OriginalAmount"]                    = 150,
+        ["OriginatorsIdentificationCode"]     = 150,
+        ["PayersReferenceParty"]              = 150,
+        ["PostingText"]                       = 30,
+        ["SepaRemittanceInformation"]         = 200,
+        ["UnstructuredData"]                  = 390,
+        ["UnstructuredRemittanceInformation"] = 390,
+        ["DebitCreditMark"]                   = 2,
+        ["TransactionTypeIdCode"]             = 3,
+    };
+
+    private static void ApplyKnownColumnWidths(DataTable tbl)
+    {
+        foreach (var (columnName, maxLength) in KnownColumnMaxLengths)
+        {
+            if (tbl.Columns.Contains(columnName) && tbl.Columns[columnName]!.DataType == typeof(string))
+                tbl.Columns[columnName]!.MaxLength = maxLength;
+        }
+    }
+
     private static DataTable BuildDefaultSchema()
     {
         var t = new DataTable();