Demo mode: any non-empty signature is accepted. Replace with real Verus signer later.
ODINID: @demo#main
Challenge: jBbmMOBWegv_pmvk3OEX0Q
Nonce: CB1CEb8JK-P7pkQGnM4O_5Qd5myalsXD
Expires in: 300s
Scan the QR with your ODINID signer to produce a signature for the nonce.