feat: Enhance user group management and transaction handling in stored procedures

- Improved user group deletion logic to accurately report success or failure.
- Updated user group renaming checks to prevent unintended inserts or updates.
- Added documentation on transaction blocking risks during full resets in stored procedures.
- Removed unnecessary login scripts from database project.

Fuchs_DataService/FdsMfrClient.cs

@@ -16,7 +16,10 @@ public class FdsMfrClient : IDisposable
     private readonly MFRClient _mfrClient;
     private readonly ILogger<FdsMfrClient> _logger;
 
-    // Full-reset merges of large entity tables exceed SqlCommand's 30 s default.
+    // Full-reset merges of large entity tables exceed SqlCommand's 30 s default. Raising this
+    // also raises how long a full-reset's mfr__updt__* transaction can hold locks and block
+    // readers of the live mfr__* tables — an accepted, documented risk, see
+    // Docs/Decisions/0022-mfr-sync-transaction-blocking-accepted-risk.md.
     private const int MergeCommandTimeoutSeconds = 600;
 
     private static MFRClientCredentials DefaultCredentials() =>
@@ -259,7 +262,13 @@ public class FdsMfrClient : IDisposable
                                 try
                                 {
                                     tbl.AcceptChanges();
-                                    var dtwa = new DatatableWriterAsync(tbl, FdsShared.FDSConnectionString());
+                                    var dtwa = new DatatableWriterAsync(tbl, FdsShared.FDSConnectionString())
+                                    {
+                                        // A large full-reset batch can exceed SqlBulkCopy's 30s default just as
+                                        // easily as the merge proc it feeds into — match CommandAfter's timeout
+                                        // so staging itself doesn't fail before the merge/fds__setStatus ever runs.
+                                        BulkCopyTimeoutSeconds = MergeCommandTimeoutSeconds
+                                    };
                                     // One fixed debug copy per entity table (last failed batch) instead of a new t_<setid>_ table per attempt.
                                     string fallbackTable = $"t_err_{tbl.TableName}";
                                     dtwa.CommandAfterError = new SqlCommand(