Run batches and import JSON or CSV through the API

Each operation is dispatched as a request of its own, so a batch is held to
the same validation and permissions as the calls it contains.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lang/en/rules.php

@@ -39,6 +39,11 @@ return [
         'not_awaiting' => 'It is not awaiting review.',
     ],
 
+    'batch' => [
+        'path' => 'Only admin API operations (/v1/…), with no nested batches or imports.',
+        'too_many' => 'At most :max rows per import.',
+    ],
+
     'settings' => [
         'read_only' => 'This setting is written by the application and cannot be edited by hand.',
     ],