fix: resolve $tenant type mismatch in validation and update detection

- Structure validator: always validate $tenant as integer regardless of
  adapter ID type, since tenant IDs are integers in all adapters
- updateDocument: use raw getAttribute instead of getTenant() to preserve
  the original type and avoid false change detection from int/string mismatch

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: abnegate

src/Database/Database.php

@@ -6054,7 +6054,7 @@ public function updateDocument(string $collection, string $id, Document $documen
             $document['$createdAt'] = ($createdAt === null || !$this->preserveDates) ? $old->getCreatedAt() : $createdAt;
 
             if ($this->adapter->getSharedTables()) {
-                $document['$tenant'] = $old->getTenant(); // Make sure user doesn't switch tenant
+                $document['$tenant'] = $old->getAttribute('$tenant'); // Make sure user doesn't switch tenant
             }
             $document = new Document($document);
 

src/Database/Validator/Structure.php

@@ -340,7 +340,8 @@ protected function checkForInvalidAttributeValues(array $structure, array $keys)
 
             switch ($type) {
                 case Database::VAR_ID:
-                    $validators[] = new Sequence($this->idAttributeType, $attribute['$id'] === '$sequence');
+                    $idType = ($attribute['$id'] === '$tenant') ? Database::VAR_INTEGER : $this->idAttributeType;
+                    $validators[] = new Sequence($idType, $attribute['$id'] === '$sequence');
                     break;
 
                 case Database::VAR_VARCHAR: