feat(api): automatically add ID and timestamps to created documents

- Implement automatic generation of 'id', 'createdAt', and 'updatedAt' fields for new documents
- Use ObjectId for 'id' and ISO 8601 string for timestamps
- Ensure UTC time is used for timestamps

Author: fulleni

routes/api/v1/data/index.dart

@@ -7,6 +7,7 @@ import 'package:ht_api/src/rbac/permission_service.dart';
 import 'package:ht_api/src/registry/model_registry.dart';
 import 'package:ht_data_repository/ht_data_repository.dart';
 import 'package:ht_shared/ht_shared.dart';
+import 'package:mongo_dart/mongo_dart.dart';
 
 /// Handles requests for the /api/v1/data collection endpoint.
 /// Dispatches requests to specific handlers based on the HTTP method.
@@ -152,6 +153,12 @@ Future<Response> _handlePost(RequestContext context) async {
     throw const BadRequestException('Missing or invalid request body.');
   }
 
+  // Standardize ID and timestamps before model creation
+  final now = DateTime.now().toUtc().toIso8601String();
+  requestBody['id'] = ObjectId().oid;
+  requestBody['createdAt'] = now;
+  requestBody['updatedAt'] = now;
+
   dynamic itemToCreate;
   try {
     itemToCreate = modelConfig.fromJson(requestBody);