POST /api/auth/verify-challenge

POST /api/auth/verify-challenge HTTP/1.1
Content-Type: application/json

{
  "did": "did:alyra:z6Mkf...",
  "challenge": "nonce-from-challenge-endpoint",
  "signature": "base64EncodedEd25519Signature"
}

{
  "success": true,
  "message": "Challenge verified successfully",
  "user": {
    "did": "did:alyra:z6Mkf...",
    "public_key": "base64-or-multibase-public-key"
  },
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

POST /api/auth/challenge
Content-Type: application/json

{
  "did": "did:alyra:z6Mkf..."
}

{
  "success": true,
  "challenge": "nonce-from-server",
  "expires_at": "2026-06-27T00:05:00Z"
}