refactor(api): unify envelope response structure

Remove redundant 'envelope' field from API response. Now returns only
the 'files' array with complete file information (id, uuid, name, status,
statusText) for cleaner and more consistent API structure.

Signed-off-by: Vitor Mattos <[email protected]>

Author: vitormattos

lib/Db/SignRequestMapper.php

@@ -666,19 +666,13 @@ private function formatListRow(array $row): array {
 
 		if ($row['node_type'] === 'envelope') {
 			$childrenFiles = $this->fileMapper->getChildrenFiles($internalId);
-			$filesData = array_map(fn ($file) => [
+			$row['files'] = array_map(fn ($file) => [
 				'id' => $file->getNodeId(),
 				'uuid' => $file->getUuid(),
 				'name' => $file->getName(),
 				'status' => $file->getStatus(),
 				'statusText' => $this->fileMapper->getTextOfStatus($file->getStatus()),
 			], $childrenFiles);
-
-			$row['envelope'] = [
-				'filesCount' => count($childrenFiles),
-				'files' => $filesData,
-			];
-			$row['files'] = $filesData;
 		} else {
 			$row['files'] = [[
 				'id' => (int)$row['node_id'],