When nginx follows a backend 307 redirect to a presigned S3 URL, it was
forwarding the client's Authorization header to S3. Production S3 rejects
this because it sees two auth mechanisms (presigned URL signature +
Authorization header). MinIO in devenv is more lenient and ignores the
extra header.
Fix: add proxy_set_header Authorization "" in the @handle_redirect block.
Fixes#10776
AI-assisted-by: mimo-v2.5-pro