Set wallet address

curl --request POST \
  --url https://app.mandate.md/api/activate \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "evmAddress": "0x71C7656EC7ab88b098defB751B7401B5f6d8976F"
}
'

{
  "activated": true,
  "agentId": "9e5f1a2b-3c4d-5e6f-7a8b-9c0d1e2f3a4b",
  "evmAddress": "0x71c7656ec7ab88b098defb751b7401b5f6d8976f",
  "onboardingUrl": "https://app.mandate.md/dashboard?onboarding=1",
  "message": "Agent activated. Tell your human to visit: https://app.mandate.md/dashboard?onboarding=1"
}