curl --request PATCH \
  --url https://api.sumvin.com/v0/user/me/username \
  --header 'Content-Type: application/json' \
  --data '
{
  "username": "john_doe"
}
'

{
  "_links": {
    "kyc-status": {
      "href": "/v0/kyc/status"
    },
    "self": {
      "href": "/v0/user/me"
    },
    "wallets": {
      "href": "/v0/wallets"
    }
  },
  "user": {
    "email": "user@example.com",
    "id": "usr_abc123"
  },
  "wallets": [
    {
      "address": "0x742d35Cc6634C0532925a3b844Bc9e7595f2bD78",
      "chain_id": 8453,
      "is_eoa": true,
      "is_primary": true
    }
  ]
}