fix(centralui): stabilize audit grid th nodes with @key; doc grid limitations

src/ScadaLink.CentralUI/Components/Audit/AuditResultsGrid.razor

@@ -17,7 +17,13 @@
                 <tr>
                     @foreach (var col in OrderedColumns())
                     {
+                        // @key keeps Blazor reusing one DOM node per column across
+                        // re-renders (reorder/resize), so audit-grid.js binds drag
+                        // listeners exactly once per <th> and never leaks them onto
+                        // discarded nodes — the __auditGridCellBound guard relies on
+                        // this node stability to be fully sound.
                         <th class="audit-grid-th"
+                            @key="col.Key"
                             data-test="col-header-@col.Key"
                             data-col-key="@col.Key"
                             style="@ColumnWidthStyle(col.Key)">