Self-register for an API key

curl --request POST \
  --url https://backend.inkwell.finance/api/v1/agents/self-register \
  --header 'Content-Type: application/json' \
  --data '
{
  "email": "jsmith@example.com",
  "agentName": "<string>",
  "suiAddress": "<string>"
}
'

{
  "success": true,
  "data": {
    "apiKey": "<string>",
    "keyPrefix": "<string>",
    "tier": "<string>",
    "status": "pending_verification",
    "rateLimits": {
      "rpm": 123,
      "rpd": 123
    },
    "warning": "<string>"
  }
}