feat(template-folder): rename folder with sibling uniqueness check

src/ScadaLink.TemplateEngine/Services/TemplateFolderService.cs

@@ -42,4 +42,29 @@ public class TemplateFolderService
 
         return Result<TemplateFolder>.Success(folder);
     }
+
+    public async Task<Result<TemplateFolder>> RenameFolderAsync(
+        int folderId, string newName, string user,
+        CancellationToken cancellationToken = default)
+    {
+        if (string.IsNullOrWhiteSpace(newName))
+            return Result<TemplateFolder>.Failure("Folder name is required.");
+
+        var folder = await _repository.GetFolderByIdAsync(folderId, cancellationToken);
+        if (folder == null)
+            return Result<TemplateFolder>.Failure($"Folder with ID {folderId} not found.");
+
+        var all = await _repository.GetAllFoldersAsync(cancellationToken);
+        if (all.Any(f => f.Id != folderId
+                         && f.ParentFolderId == folder.ParentFolderId
+                         && string.Equals(f.Name, newName, StringComparison.OrdinalIgnoreCase)))
+            return Result<TemplateFolder>.Failure($"A folder named '{newName}' already exists at this level.");
+
+        folder.Name = newName;
+        await _repository.UpdateFolderAsync(folder, cancellationToken);
+        await _repository.SaveChangesAsync(cancellationToken);
+        await _auditService.LogAsync(user, "Update", "TemplateFolder", folder.Id.ToString(), newName, folder, cancellationToken);
+
+        return Result<TemplateFolder>.Success(folder);
+    }
 }