uploadBedrockRelay
public Optional<MagmaguyRspClient.BedrockRelayEntry> uploadBedrockRelay(String networkKey, String backendId, String kind, File file, String sha1HexOrNull)
Upload a Bedrock pack (kind="zip") or Geyser mappings file (kind="mappings") to the relay under this network. The relay stores by (sha256(networkKey)[:32], backendId, kind) — re-uploading the same triple overwrites the previous file and resets its TTL.