fix: rewrite temp files with PutObject instead of SeaweedFS CopyObject

CopyObject returns InternalError 500 across buckets, so commits now Get+Put and ensure the documents bucket exists on startup.

app.js

@@ -115,6 +115,9 @@ const startServer = async () => {
     await seedDatabase({ disconnectOnComplete: false });
   }
 
+  const { ensureAppBuckets } = require('./utils/s3Client');
+  await ensureAppBuckets();
+
   const registerEventListeners = require('./events/eventListeners');
   const { startPaymentReminderJob } = require('./jobs/paymentReminderJob');
   const { startNotificationRetryJob } = require('./jobs/notificationRetryJob');