Files uploaded by users were lost on every container rebuild.
Named volume uploads_data mounts to /app/uploads and is managed by Coolify.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Without this, files were saved with http://localhost:3000/uploads/... URLs
which are unreachable from the browser. Now uses the public backend domain.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>