fix: Skip export attachments with malformed key (#12470)

Attachments whose key ends in a trailing slash have no filename
component and cause yazl to throw, aborting the entire export. Skip
them with a warning and continue the export instead.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

server/queues/tasks/ExportDocumentTreeTask.ts

@@ -70,6 +70,17 @@ export default abstract class ExportDocumentTreeTask extends ExportTask {
         key: attachment.key,
       });
 
+      // Skip attachments with a malformed key that has no filename component,
+      // as yazl rejects entries whose path ends with a slash.
+      if (!attachment.key || attachment.key.endsWith("/")) {
+        Logger.warn(`Skipping attachment with invalid key`, {
+          attachmentId: attachment.id,
+          teamId: attachment.teamId,
+          key: attachment.key,
+        });
+        continue;
+      }
+
       const dir = path.dirname(pathInZip);
       let buffer: Buffer;
       try {